Introduction to this issue of electrochemical battery technology is a major growth point in the current energy storage industry. lead carbon battery has high cost performance and initial commercialization has been achieved; the expansion of lithium battery capacity has driven a rapid decline in costs, and the economy of energy storage is becoming stronger. The cost of liquid flow and sodium sulfur is high, and technology needs to be broken through.
Summary
lead carbon has significant cost-effective advantages and is promising in the market prospects. Lead carbon technology can increase the cycle life of ordinary lead-acid battery by 3-4 times, increase the charging speed by 6 times, and increase the charging speed by 8 times. Its production cost is only 30-40% higher than that of ordinary lead-acid battery, which is extremely cost-effective. Currently, the lead-acid battery industry has formed a circular industrial chain of "raw materials-production-application-recycling". Lead-carbon energy storage technology has been based on this and has initially achieved commercial application in many fields, with a promising market prospects.
The lithium battery industry is developing rapidly, and the decline in costs promotes the application of energy storage. The scale of the lithium battery cell industry exceeds 200 billion and will continue to maintain rapid growth in the future. The cost of lithium batteries has dropped by more than 50% in the past three years. Currently, the production capacity of mainstream lithium battery manufacturers is still expanding rapidly. With the advancement of electrode technology and the cascade utilization of power batteries, it is expected that the cost of lithium batteries will still maintain an annual decline of 15-20% in the next five years, and the cost of lithium battery energy storage will also enter the commercialization range.
Lithium battery technology is the mainstream of electrochemical energy storage. Lithium battery energy storage has technological and economic advantages in various application fields. At present, the installed capacity of related projects around the world accounts for about 50% of the total capacity, far exceeding other energy storage technologies. Energy storage applications pay more attention to safety, cycle life and cost. Currently, lithium iron phosphate and lithium titanate technologies are more suitable. In the future, advanced negative electrode technology and electrolyte technology will become the key to improving cycle life.
flow battery systems are numerous, and all vanadium and zinc bromine are the mainstream. The flow battery has good circulation performance, and its capacity and power can be adjusted independently, which is suitable for large-scale energy storage. There are many researches on all vanadium systems in China, but the cost of diaphragm relies on imports. Zinc bromine costs are relatively low, and technology is still monopolized by foreign countries. Single flow batteries do not require diaphragms, which is a new direction for the development of flow battery technology in the future.
Sodium sulfur energy storage performance is good, and it is difficult to promote in the short term. sodium sulfur battery has been used more maturely abroad, but its core technology is monopolized by Japan and is difficult to promote in the short term. Due to its high working temperature, there are also some hidden dangers in terms of safety.
Recommended targets: Shanshan Co., Ltd. , Guoxuan Hi-Tech , Kelu Electronics
Benefits: Nandu Power , Shengyang Co., Ltd., Mengshi Technology, Xiongtao Co., Ltd., GCL Integrated
Risk warning: Energy storage is still in the early stage of the industry, and the development progress may not meet expectations.
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1 The development of the energy storage industry is accelerating, and electrochemical technology is a hundred schools of thought
Electrochemical battery technology is a major growth point in the current energy storage industry. As of the end of 2016, the global installed capacity of electrochemical energy storage reached 1756.5MW, with a compound growth rate of 27.5% in the past five years. my country's energy storage industry started relatively late. After more than ten years of development, it is currently transitioning from small-scale research and demonstration to early stages of commercialization. In 2016, my country's installed capacity of chemical energy storage was 189.4MW, a year-on-year increase of 79.5%. Compared with other energy storage methods, electrochemical energy storage has the advantages of good equipment mobility, fast response speed, high energy density and high circulation efficiency, and is a hot topic in domestic and foreign energy storage research.
energy storage batteries have many types and different performance characteristics. Currently, mainstream electrochemical energy storage technologies include advanced lead-acid batteries, lithium-ion batteries, , flow batteries and sodium-sulfur batteries, etc. Their performance characteristics and economics are different. At present, no technology can fully meet the five key energy storage technical indicators of cycle life, scale, safety, economy and energy efficiency. Lead-carbon batteries and lithium batteries are electrochemical energy storage technologies that are currently developing rapidly and are expected to be the first to drive the commercialization of energy storage.
Table 1: Comparison of mainstream electrochemical energy storage technology performance
Data source: "Energy Storage Industry Research White Paper 2016", Guotai Junan Securities Research
2 Old lead acid tree has new branches, lead carbon energy storage has entered the early stage of commercialization
lead storage batteries have a long history, and technological innovation and expansion of energy storage applications. Lead-acid batteries have a history of more than 150 years since their invention in 1859.To this day, traditional lead-acid batteries still have a stable position in the field of secondary power applications due to their safety and reliability, large capacity and high cost performance. In recent years, the emergence of emerging lead-acid technologies represented by lead-carbon batteries has greatly made up for the shortcomings of traditional lead-acid batteries, such as low energy and short life, making it possible to apply them in the field of large-scale energy storage. At present, the lead-acid battery industry has a relatively mature technical system and industrial chain. Advanced lead-acid batteries benefit from relatively low production costs and are expected to be the first to commercialize in the field of large-scale energy storage.
Figure 2: The lead-acid battery industry has formed a circular industrial chain of "raw materials-production-application-recycling"
Data source: Guotai Junan Securities Research
Table 2: Advanced technology enhances the vitality of lead-acid batteries
Data source: "Main progress in my country's energy storage battery technology", Guotai Junan Securities Research
Lead-carbon batteries are the mainstream direction of the current development of advanced lead-acid technology. The core of lead carbon technology is to introduce activated carbon into the negative electrode, so that the battery has the advantages of both lead-acid batteries and supercapacitors. At the same time, it can effectively suppress the irreversible sulfateization of the negative electrode of ordinary lead-acid batteries, and significantly improve its high-current charging and discharge performance and cycle life. The test evaluation results show that under the same working conditions, the discharge power of lead-carbon batteries is 3-4 times that of ordinary lead-acid batteries, the cycle life is increased to 6 times, and the charging speed can be increased by 8 times, while its production cost is only 30-40% higher than that of ordinary lead-acid batteries. The current focus of the research on lead carbon technology is on issues such as the mechanism of action of lead carbon negative electrode, the selection of carbon materials and the inhibition of hydrogen evolution. Companies and institutions such as ALABC, AxionPower, Furukawa, CSIRO in Australia, and CEA-INESD in France are actively engaged in research and development in related aspects. Nandu Power Supply is a leading enterprise in the development and promotion of lead-carbon batteries in China, and its products and technologies have formed certain competitive advantages in the domestic market.
Figure 3: Schematic diagram of lead-carbon battery structure
Data source: "Principles of Lead-acid Battery Technology"
Figure 4: Advanced lead-acid energy storage system widely used in the power grid
Data source: "Advanced Lead-carbon Battery Energy Storage Technology"
Table 3: Development history of lead-carbon technology
Data source: "Advanced Lead-carbon Battery Energy Storage Technology", Guotai Junan Securities Research
Lead-carbon energy storage has entered the early stage of commercialization, with a large market space. Taking Nandu Power Supply as an example, the company has put into operation 48 lead-carbon energy storage projects in China, with a total scale of 242MWh, and has signed a commercial energy storage power plant project of about 1000MWh. The system is widely used in peak and frequency regulation, wind and light storage, user-side energy storage and other fields, and has broad commercial prospects. Compared with other mainstream electrochemical energy storage technologies such as lithium batteries, the cost of lead-carbon batteries is only one-third of them, and the short-term cost-effectiveness advantage is still significant. In the long run, lead-carbon batteries still have certain limitations in terms of cycle life, environmental impact, etc. It is expected that the development of other electrochemical energy storage technologies and further reduction in costs in the future will pose certain challenges to their market space.
Table 4: Lead carbon energy storage has been commercially used in multiple fields
Data source: "Introduction to the commercialization model of Nandu Energy Storage Power Station", Guotai Junan Securities Research
3 Flow battery coexisting multiple systems, all vanadium and zinc bromine are the mainstream
Flow battery with a wide variety of power capacity. The flow battery mainly undergoes an electrochemical reaction on the inert electrode through redox pairs to complete energy storage and release. Its biggest feature is that the battery output power and capacity are independent of each other, and independent design can be achieved by changing the size of the battery module, the concentration and volume of electrolyte . At the same time, the flow battery has the characteristics of good charging and discharging performance and long cycle life, and is suitable for large-scale energy storage applications. Currently, the more mature flow battery systems include dual-liquid systems such as all vanadium, zinc bromine, ferrochromium, sodium polysulfide-brominated. Among them, all vanadium and zinc bromine batteries have developed particularly rapidly due to the absence of cross-contamination of positive and negative electrode electrolytes. In addition, the zinc-nickel single-liquid system that has begun to develop in recent years also has its unique advantages.
Figure 5: Schematic diagram of the working principle of dual-flow batteries
Data source: Guotai Junan Securities Research
Figure 6: Schematic diagram of the working principle of single-flow batteries
Data source: Guotai Junan Securities Research
Table 5: There are many liquid flow battery systems
Data source: Guotai Junan Securities Research
All-vanadium liquid flow battery is the most widely studied and applied liquid flow battery technology. The positive and negative electrode pairs of all vanadium system are VO2+/VO2+ and V2+/V3+ respectively. The main advantages are that the electrolyte has no cross-contamination, no self-discharge, good consistency, and extremely long cycle life. Currently, there are 40-50 vanadium battery systems installed worldwide, and its R&D and manufacturing companies mainly include Sumitomo Electrician SEI, Dalian Rongke, Beijing PuNeng, and UniEnergy Technologies in the United States. Among them, the 200MW/800MWh Dalian liquid flow battery energy storage peak-shaving power station national demonstration project, which was invested and built by Rongke Energy Storage in 2016, is currently the largest chemical energy storage peak-shaving power station in the world.
High cost is the main factor restricting the commercialization of all vanadium flow batteries. The current cost of all vanadium systems is about 4,500-6,000 yuan/kWh, which is far higher than electrochemical energy storage technologies such as lead carbon and lithium batteries. The main reason is that the cost of materials such as ion exchange membrane and electrolyte are relatively high. At present, ion exchange membranes are heavily dependent on imports, with prices of about 5,000 yuan/square meter, and domestic prices are as high as 1,000 yuan/square meter. At the same time, the volume density of vanadium batteries is low and the electrolyte is used is large, resulting in a high total cost of batteries at the same scale. At present, the liquid flow battery industry chain has not been improved, and the future cost reduction will depend on research on the localization of ion exchange membranes, improving vanadium ion solubility, and increasing current density.
Figure 7: Key technologies for all vanadium liquid flow batteries
Data source: "all vanadium liquid flow batteries", Guotai Junan Securities Research
zinc bromine system is low in cost, and material accessories are monopolized. The structure of zinc-brominated flow battery is similar to that of all vanadium systems. The positive and negative electrode pairs are Br/Br- and Zn/Zn2+, and both elements are rich and easy to obtain. Its structural parts mainly use low-priced plastic, without precious metals, and have low cost. The separator materials are mainly microporous membranes similar to lithium batteries and lead-acid batteries. The price is relatively cheap, only 50-100 yuan per square meter. At the same time, its volume energy density is relatively high, and the overall system cost is only half that of all vanadium flow batteries, so it has attracted more attention. The main problem of zinc-bromine batteries at the technical level is the strong corrosiveness of bromine, and their material technology and accessories production are still monopolized by the United States, Japan and other countries to a certain extent. At present, the main enterprises engaged in related research and development in my country include Anhui Mineng, Beijing Baineng, etc.
zinc-nickel single-liquid system opens up a new path to the development of liquid flow batteries. Zinc nickel single-flow battery is a new type of flow battery proposed by the PLA Chemical Defense Research Institute in 2007. Its characteristics are that the same electrolyte is used for the positive and negative electrode reactions, and no ion exchange membrane is required, which greatly reduces production costs and simplifies battery design. Due to the use of alkaline electrolyte, the battery has good corrosion resistance in the long term. After testing, the battery's energy efficiency reached 86% after 1,000 cycles, which is better than the general dual-flow battery. At present, this type of battery is still in the research and development and testing stage. In addition to some domestic institutions, Japan and the United States have also begun related research.
Figure 8: Zinc nickel single flow battery cell (left) and battery pack (right)
Data source: "Flow Battery Energy Storage Technology"
4 sodium sulfur battery technology is monopolized, and it is difficult to promote domestically in the short term
sodium sulfur battery has good performance and is relatively mature in foreign applications. Sodium-sulfur batteries use elemental sulfur and metal sodium as the positive and negative electrodes, and β-alumina ceramics as the electrolyte and separator. Their working temperature is between 300-350 degrees Celsius, and have the advantages of high energy density, good power characteristics, long cycle life and relatively low cost. At present, more than 200 sodium-sulfur battery energy storage power stations have been built around the world, accounting for about 30-40% of the total installed capacity of electrochemical energy storage in the world, second only to lithium-ion batteries. Japan's NGK is the only company in the world that has the ability to produce sodium-sulfur batteries on a large scale, with an annual production capacity of about 150MW.
Figure 9: Schematic diagram of the principle and structure of sodium-sulfur batteries
Data source: "Sodium-sulfur battery Research and Analysis"
Sodium-sulfur battery cost and safety need to be optimized.The cost of sodium-sulfur battery system is about 2,000-2,500 yuan/kWh, which is relatively low compared to most energy storage technologies, but it is still far from the standard of large-scale commercialization. In addition, since the battery uses liquid sodium and operates at high temperatures, once the ceramic dielectric is damaged and broken, it will cause a major safety accident to burn the battery. In 2011, the NGK company system burned on the client side, which aggravated the market's concerns about the safety of the technology.
Domestic sodium sulfur development started late and it was difficult to promote it in the short term. The domestic sodium-sulfur battery research and development work started late, and is currently mainly undertaken by Shanghai Silicate Institute. It has successfully developed a 100kW-level energy storage system. However, compared with Japan's NGK technology, domestic sodium-sulfur technology still has a 15-20-year gap, and it is difficult to commercially promote it in the short term.
Figure 10: Sodium-sulfur battery preparation process
Data source: "Several battery frontier issues and future battery development direction", Guotai Junan Securities Research
5 The lithium battery industry is developing rapidly, and the decline in costs promotes the wide application of energy storage applications
lithium-ion batteries, and the demand for power lithium battery drives the rapid development of the industry. Lithium-ion batteries are composed of positive and negative electrodes, separators, and electrolytes. They have many advantages such as large energy density, wide working temperature range, no memory effect, fast charging and discharging, and environmentally friendly. They are currently widely used in various electronic products, new energy vehicles, electrochemical energy storage and other fields. In recent years, the lithium battery industry has been driven by the growth in demand for downstream new energy vehicles, and its scale and technology have developed particularly rapidly. At present, there are hundreds of power battery companies, with a battery cell market size exceeding 200 billion. It is expected that domestic lithium battery demand will continue to maintain a high growth rate of 30%-40% in the next five years, and the technology and industrial chain will further mature.
Figure 11: Schematic diagram of the working principle of lithium-ion batteries
Data source: GBII
Figure 12: Domestic market demand for lithium batteries maintains rapid growth
Data source: Guotai Junan Securities Research
Figure 13: Lithium-ion battery industry chain
Data source: Guotai Junan Securities Research
Lithium-ion battery technology routes, energy storage pays more attention to safety and long-term costs. Compared with power lithium batteries, lithium batteries for energy storage have relatively loose requirements for energy density, but have higher requirements for safety, cycle life and cost. From this perspective, lithium iron phosphate batteries are a technical route suitable for energy storage among all kinds of lithium-ion batteries at this stage. Most of the lithium battery energy storage projects that have been invested in and built also use this technology. In addition, lithium titanate batteries have also received widespread attention due to their ultra-long cycle life. With the reduction of technological costs in the future, they are expected to achieve large-scale application in the field of energy storage. The main advantage of ternary batteries is their high energy density, their cycle life and safety are relatively limited, so they are more suitable for use as power batteries.
Table 6: Lithium iron phosphate and lithium titanate technologies are more suitable for energy storage applications
Data source: Guotai Junan Securities Research
Lithium battery scale economic effect has emerged, and energy storage costs have dropped rapidly. In recent years, the domestic power lithium battery industry has been fiercely competitive. The downstream vehicle manufacturers' demand for performance and price has forced the rapid progress of lithium battery technology. At the same time, the production capacity of major manufacturers has been continuously expanding, and the production cost of lithium battery continues to decline, with an average annual decline of 15-20%. At present, the price of lithium iron phosphate batteries in some manufacturers has dropped to 1,200-1,400 yuan/kWh, and the corresponding energy storage system cost has also dropped to 2,000 yuan/kWh, which has greatly improved the economy of energy storage. Judging from the currently announced plans, the trend of rapid expansion of production capacity of major lithium battery manufacturers in the next few years will continue, and lithium battery energy storage will also enter the commercial application range as costs decrease.
Figure 14: The cost of lithium-ion batteries has dropped rapidly in recent years
Data source: electronic enthusiasts, Guotai Junan Securities Research
Figure 15: Domestic power lithium battery manufacturers' rapid expansion of production capacity
Data source: Guotai Junan Securities Research
cascade utilization can further improve the economicality of lithium battery energy storage. The cascade utilization technology is mainly aimed at retired power batteries with reduced capacity but not completely scrapped. Its main links include recycling and performance evaluation, battery system restructuring and cascade utilization in the field of energy storage. It is a green, economical and sustainable resource recycling method.Relevant research is currently being actively carried out around the world, and there are many successful cases in countries such as the United States, Germany, and Japan that started earlier. Domestic first-line power battery manufacturers such as BYD , CATL, Guoxuan Hi-Tech, and AVIC Lithium Battery have begun to deploy in related fields, which is expected to further reduce the cost of lithium batteries in the future.
Table 7: Various types of power battery cascade utilization energy storage demonstration projects have been gradually carried out at home and abroad
Data source: "Power Battery Cylinder Utilization Report"
Energy storage 100 billion market will be launched, and lithium battery technology is the mainstream. Lithium battery energy storage has the advantages of cleaning and efficient, high energy density, good charging and discharging performance, and fast response speed, and has technical and economic advantages in many application fields. Among the MW-level electrochemical energy storage demonstration projects that have been built around the world, the installed scale of lithium battery projects accounts for about 50% of the total capacity, far exceeding other energy storage technologies. Large-scale energy storage demonstration projects such as Zhangbeifeng Optical Storage and Transmission and Nanwang Baoqing Power Station in China have also developed lithium batteries as a key technical route. With the continuous rapid development of the lithium battery industry and the continuous reduction of battery costs, it is expected that lithium-ion batteries will remain the mainstream of electrochemical energy storage in the future.
Figure 16: The domestic energy storage installation scale is the largest lithium battery
Data source: CNESA
Table 8: Lithium batteries have technological and economic advantages in multiple application fields
Data source: CNESA Energy Storage Industry Research White Paper 2016, Guotai Junan Securities Research
6 Recommended and beneficiary target
Recommended target
Shanshan Co., Ltd.: Starting energy storage operation business from 2017. Shanshan Co., Ltd. is a leading new energy enterprise in my country. It has fully deployed from lithium battery materials to power lithium battery PACK to motor and electronic control BMS to complete vehicles and complete vehicles operations, and has complete technical reserves in the field of energy storage. Starting from 2017, the Energy Storage Industry Fund will be established to carry out energy storage peak-cutting and valley filling operation business.
Guoxuan Hi-Tech: The leader in power lithium batteries accelerates the layout of the energy storage industry. The company is one of the leading domestic power lithium batteries, with strong technical R&D capabilities and a stable customer base. Currently, the company is actively promoting the research and development of power lithium batteries in the process of using power lithium batteries, with the intention of achieving breakthroughs in battery energy storage, battery recycling, mobile power supply, backup power supply, etc. The company recently signed a 200MW energy storage power plant project with the 11th Design Institute of Information Industry Electronics Technology Engineering Co., Ltd. and Beijing Fuweis Oil and Gas Technology Co., Ltd., laying the foundation for the technology development and application of the three parties in energy storage power plants, microgrid systems and other projects.
Kelu Electronics: Actively deploy the energy storage market, and the frequency regulation project will be put into operation in the near future. Since 2009, the company has been in the field of energy storage and has participated in the construction of about 120 energy storage power plants. It currently has leading technologies in "wind, light, storage and transmission" virtual power plants, unmanned on-site energy storage and storage power plants on demand side, and energy storage equipment cloud platform systems based on the Internet of Things. Since last year, the company has won the bid for a number of energy storage projects such as "Tibet Shuanghu County 3MW Renewable Energy Local Area Network Project" and "Tibet Golden Sun Solar Energy Household System Project". It has begun to build a 400 million Ah fully automatic high-performance lithium-ion energy storage battery production line, supporting 10,000 tons of lithium iron phosphate project and corresponding diaphragm and electrode sheet manufacturing. Recently, the Shanxi Tongda Power Plant Energy Storage AGC Frequency Regulation Project, invested by Zhongan Chuangying Energy Technology Industry Co., Ltd. and built by the company, was successfully completed and will be put into operation soon. It is expected to have a positive impact on the company's main business growth and sustainable profitability.
Benefiting target
Nandu Power Supply: Comprehensive layout of the energy storage industry and expand overseas energy storage market. The company is a leader in the field of large-scale energy storage and distributed microgrid energy storage in China. It has internationally leading lead-carbon battery technology and rich experience in energy storage promotion and application. It has currently put into operation 45 energy storage demonstration projects and has signed the "Investment + Operation" commercial energy storage power station project of about 1,000MWh. The company recently completed the acquisition of the remaining 49% equity of Huabo Technology, the leading domestic recycled lead, further improving its lead cycle industry chain and forming a strong industrial synergy with its lead-carbon battery business. At the same time, the company actively expands the overseas energy storage market and uses the German Upside company to build a 50MW energy storage power station for primary frequency regulation services. The company's energy storage project is currently mainly carried out by the "investment + operation" model, and the relevant information has been widely recognized by the market.It is expected that 2017 will be the year when the company's energy storage business enters large-scale construction and realizes its performance.
Shengyang Co., Ltd.: Relying on lead-carbon technology to expand the energy storage market. The company is one of the earliest companies in China to independently develop and produce valve-controlled sealed lead-acid batteries. In recent years, it has actively deployed in the new energy field. Its lead-carbon batteries, high-temperature batteries, lithium-ion batteries, new energy energy storage systems and other technologies are at the leading level in the industry. The lead-carbon batteries developed by the company in cooperation with Japan's Fukukawa Company have been mass-used in the domestic and foreign energy storage markets, including Haidao Micronet, photovoltaic energy storage, communication peak shifting and valley filling and other fields. In 2016, the company's operating income of new energy and emergency energy storage batteries reached 47.07%, a year-on-year increase of 12.9%, and the gross profit margin was about 23.2%. In the future, the company will further expand the application of energy storage on the power generation side and communication base stations.
Xiongtao Co., Ltd.: Actively explore the energy storage market. The company is one of the largest exporters of industrial lead-acid batteries in China. In recent years, it has actively deployed in new energy lithium batteries, smart energy storage and other fields. Its business types cover product development, solution solutions, system integration, investment and operation, etc. For different applications such as home energy storage and grid energy storage, the company has developed a variety of solutions such as EnerMax and EnerCube, and the main needs come from Australia, Europe and the United States. Recently, the company's container modular energy storage units have begun to be put into production in batches, mainly using independently developed lithium iron phosphate/lead carbon battery technology. The company's current investment in the new energy field has not yet received corresponding returns. At the same time, due to the 4% consumption tax policy imposed by lead-acid batteries in 2016, the company's short-term net profit has declined.
Mengshi Technology: Expand clean power business and lay out the construction of energy storage power stations. Based on the lithium battery and lead-acid battery industries, the company has established a complete industrial chain covering clean energy power generation, energy storage, intelligent power transmission and distribution, smart energy management, and power sales services, from the power supply side to the demand side, and has the ability to build and operate microgrids. In 2016, 56% of the company's operating income came from the clean power industry, and its energy storage business was mainly implemented by Jiangsu Fengguyuan and German subsidiary Durion Energy AG. At present, the company is actively expanding its energy storage business at home and abroad, and its German 100MW lithium-ion battery energy storage power station project has started preliminary construction preparations.
GCL integration: layout user-side energy storage and focus on developing overseas markets. The company will focus on distributed projects between 6MW and 20MW, including household roofs, industrial and commercial photovoltaic roofs, fishing and light complementarity, and agricultural photovoltaic complementarity. By promoting "photovoltaic + energy storage", "photovoltaic + diesel power generation", "photovoltaic + off-grid system" and other models, it will provide system integrated products and services. In terms of energy storage technology, the company will promote the development of high-energy silicon composite anode materials and long-life anode materials for lithium titanate. At present, the company has independently developed its first energy storage product, E-KwBe, and its advantages in technology, quality and cost-effectiveness have been recognized by the market and have certain market competitiveness.
7 Risk warning
Energy storage is still in the early stages of the industry, and its development progress may not meet expectations. Energy storage as a whole is still in its early stages of development. 2017 may be the first year of energy storage development. Since the industry is still immature, the development progress is likely to be lower than expected.
