Electrochemical energy storage
Electrochemical energy storage is an energy storage technology that stores electrical energy using chemical batteries and releases it when needed. It can be understood as a large power bank. Compared with other energy storage methods, electrochemical energy storage has the characteristics of large capacity and fast response. With the development of the new energy industry, electrochemical energy storage technology has ushered in broad development space.
Development Background of Electrochemical Energy Storage Industry
Since 2022, the newly added scale of electrochemical energy storage in China has significantly increased. According to the "Statistical Data of the Electrochemical Energy Storage Power Station Industry", from January to August 2022, 64 new electrochemical energy storage power stations were put into operation in China, with a total of 1.29GWh of newly added energy put into operation; 158 electrochemical energy storage power stations are under construction, with a total energy of 8.77 GWh.
Electrochemical energy storage is the first energy storage technology to achieve industrial application among new energy storage technologies. Electrochemical energy storage technology has the characteristics of high conversion efficiency, fast response speed, and flexible configuration, which can effectively meet the needs of peak shaving and frequency regulation in new power systems. Therefore, it is the first to achieve industrial application in the new power system.
According to CNESA data, the cumulative installed capacity of global electrochemical energy storage accounted for 95.7% of the cumulative installed capacity of new energy storage in 2021, with lithium batteries, sodium sulfur batteries, lead batteries, and liquid flow battery energy storage technologies accounting for 90.9%, 2%, 2.2%, and 0.6%, respectively.
Classification and Development Opportunities of Energy Storage Batteries
Electrochemical energy storage refers to various types of secondary battery energy storage, mainly including lithium-ion batteries, lead batteries, and sodium sulfur batteries. At present, the technology of energy storage lithium batteries is relatively mature, and the industry is expected to continue its prosperity. The energy storage technology of all vanadium flow batteries has entered a stage of accelerated development. With the industrialization of energy storage sodium batteries, their future development prospects are broad.
1. Lead acid battery: A type of secondary battery that uses lead dioxide as a positive battery, metal lead as a negative battery, and sulfuric acid solution as an electrolyte. It has a history of over 150 years and is an early large-scale secondary battery.
Lead acid batteries have low energy storage costs, good stability, and high efficiency, and are widely used in UPS. They are also the leading technology route for large-scale electrochemical energy storage in China in the early stage. However, due to the short cycle life, low energy density, narrow temperature range, slow charging speed, and significant environmental impact of lead metal, the future application of lead-acid batteries will be greatly limited.
2. Lithium ion batteries: Energy storage and release are achieved through the reversible transfer of lithium ions between positive and negative ions.
The development of lithium battery energy storage technology is mature, but its safety needs to be improved.
At present, lithium batteries for energy storage are the main technological form of electrochemical energy storage. According to the 2022 Energy Storage Industry Application Research Report, the global installed capacity of lithium battery energy storage technology reached 19.85GW in 2021, achieving large-scale application. However, there are certain safety hazards in the application of lithium batteries in the energy storage field, which usually occur in the form of thermal runaway.
In addition, lithium batteries also face the problem of high raw material lithium carbonate prices. According to data from Baichuan Yingfu, as of October 28, 2022, the average market price of lithium carbonate was 559000 yuan/ton, an increase of 110.2% compared to the beginning of 2022, providing opportunities for the development of other electrochemical energy storage technologies.
3. Liquid flow battery: According to the electrolyte, it can be divided into all vanadium flow, sodium polysulfide flow, zinc bromide flow, and iron chromium flow. Currently, all vanadium flow is the mainstream.
The proportion of liquid flow batteries in electrochemical energy storage technology is relatively low, and their development has entered a stage of acceleration. Compared to lithium batteries, all vanadium flow batteries have advantages such as high safety and long cycle life, making them suitable for long-term energy storage. With the continuous maturity of all vanadium flow battery technology, its cost is expected to gradually decrease, promoting its development and acceleration.
According to the energy storage data of Gaogong, since 2021, several large-scale all vanadium flow battery projects with a capacity of 100 MWh have been launched in China. According to data from Cailian News Agency, the domestic * GWh all vanadium liquid flow energy storage power station started construction on September 20, 2022 in Chabuchar County, Xinjiang, and is planned to be connected to the grid by the end of 2023.
In the same month, CNNC Huineng announced the centralized procurement of domestic * 1GWh all vanadium flow battery energy storage systems. Sodium batteries are based on lithium battery technology and are currently in the stage of industrialization, with broad development prospects.
4. Sodium ion battery: Positive * is composed of liquid sulfur, negative * is composed of liquid sodium, and the operating temperature of the battery is maintained above 300 ℃ to keep the battery in a molten state. The advantages are that it is cheaper than lithium ion and has larger storage space, while the disadvantages are safety hazards.
The working principle of sodium batteries is similar to that of lithium batteries, with high safety, low cost, and good low-temperature performance, which can meet the standard requirements of energy storage systems.
According to the official website of Zhongke Haina, in mid March 2019, Kehai Sodium released the world's first 30 kW/100kWh sodium ion battery energy storage power station, and in June 2021, launched a 1MWh sodium ion battery energy storage system. According to data from China Energy Storage Network, the world's first 100kWh sodium ion battery digital energy storage system prototype was powered up in Ulanqab in November 2021.
The Development History of Electrochemical Energy Storage Industry
Although China's energy storage industry started relatively late, its development speed in recent years has been impressive. Overall, the electrochemical energy storage market in China can be roughly divided into four development stages:
1. The technical validation stage (2000-2010) mainly involves basic research and development and technical validation demonstration.
2. In the demonstration application stage (2011-2015), through demonstration projects, the performance of energy storage technology has been rapidly improved, the application mode has been continuously clarified, and the application value has been widely recognized.
In the early stage of commercialization (2016-2020), with increasing policy support, gradually streamlining market mechanisms, and integrating and infiltrating multiple fields, the scale of energy storage installation rapidly increased, and the business model gradually established.
4. In the stage of industrial scale development (2021-2025), energy storage projects are widely used, technological levels are rapidly improving, and standard systems are becoming increasingly perfect, forming a relatively complete industrial system and a group of internationally competitive market entities. Energy storage has become a new economic growth point in the energy field.
With the proposal of the "30-60 carbon peak carbon neutrality" strategy, renewable energy sources such as photovoltaic and wind power will become the main energy sources. However, these renewable energy sources do not match the electricity load and require a large amount of energy storage to undertake the role of peak shaving and valley filling. In addition, a high proportion of renewable energy will put forward higher requirements for the flexible regulation ability of the power system, which also brings new opportunities for the development of energy storage.
Energy storage industry chain
A complete electrochemical energy storage system mainly consists of battery packs, battery management systems (BMS), energy management systems (EMS), energy storage converters (PCS), and other electrical equipment.
The battery pack is the main component of the energy storage system, responsible for energy storage; The battery management system is mainly responsible for monitoring, evaluating, protecting, and balancing batteries; The energy management system is responsible for data collection, network monitoring, and energy scheduling; The energy storage converter can control the charging and discharging process of the energy storage battery pack, and perform AC/DC conversion.
The upstream of the energy storage industry chain mainly includes suppliers of batteries, battery management systems, energy management systems, and energy storage converters; The midstream is a system integrator and installer, while the downstream mainly consists of end users. Batteries are an important part of electrochemical energy storage systems, accounting for 60% of the cost of energy storage systems. PCS accounts for 20%, EMS accounts for 10%, BMS accounts for 5%, and other accessories account for 5%.
In the future, with the industrialization of sodium batteries, they are expected to be widely applied in the field of energy storage. Overall, in the context of "dual carbon", electrochemical energy storage is expected to benefit from industry development opportunities.