Energy storage was rated as one of the top ten new technologies that may change the world in the future by the Davos Economic Forum. Energy storage batteries are the most active field in the development and application of energy storage technologies. At present, energy storage battery technology is developing rapidly. Once a breakthrough is made, it will have a major impact on the development of new energy, grid operation control, and terminal energy use methods. In the future, energy storage battery technology will be widely used in the new generation of power systems.
▌New energy storage battery technology has become a hot spot and technological frontier of current research and development
Existing commercial battery technologies include lithium ion batteries, lead-acid batteries, nickel-metal hydride/cadmium batteries, sodium-sulfur/nickel batteries, etc. These battery technologies are mature and have been widely used in electric vehicles, mobile phones, notebook computers, wind farm energy storage systems, Grid frequency modulation, distributed power and microgrid fields.
At present, there are more than 30 new energy storage batteries in commercial and demonstration applications, laboratory research and development or conceptual design stages. Among them, the battery technologies that have been demonstrated and applied include ternary material lithium-ion batteries, all-vanadium/zinc-bromine flow batteries, lead-carbon batteries, supercapacitor batteries, etc.; battery technologies in the laboratory development stage include graphene/lithium-sulfur/lithium Air and other new-generation lithium-ion batteries, semi-solid/non-film and other new-generation flow batteries, aluminum/zinc and other metal-air batteries, sodium/magnesium ion batteries, liquid metal batteries, etc.; graphene supercapacitor batteries, dual-carbon batteries, nano Micro batteries, organic batteries, etc. are in the conceptual design stage. These new energy storage battery technologies have become the current research and development hotspots and technological frontiers. In the future, they are expected to greatly improve the performance of energy storage batteries and promote large-scale applications of energy storage batteries.
Semi-solid flow batteries combine the advantages of lithium-ion and flow batteries, and will achieve a qualitative leap in improving battery energy and power density, reducing size, and reducing costs. At present, the Massachusetts Institute of Technology has developed a semi-solid flow battery with an energy density of 250 Wh/kg, which is more than 10 times higher than the current flow battery, and the cost is only US$100 to $250/kWh, which is 70% lower than the current one. the above. Graphene lithium batteries use graphene with high conductivity and ultra-light weight as materials, and use the characteristics of lithium ions to quickly shuttle between the graphene surface and the electrodes, reducing the charging time to minutes. Spain's Graphenano company and the University of Cordoba have jointly developed the world's first graphene battery for electric vehicles. The charging time is only 8 minutes and the cruising range reaches 1,000 kilometers. The theoretical energy density of lithium-sulfur batteries can reach 2,600 Wh/kg, which is 8 to 10 times that of traditional lithium-ion batteries. The energy density of lithium-sulfur batteries developed by Polyplus in the United States and Fraunhofer Institute of Materials and Beams in Germany has reached 420 Wh/kg and 600 Wh/kg. The aluminum-air battery uses air as the positive electrode and aluminum as the negative electrode. Energy is released through a chemical reaction between aluminum and oxygen. Theoretically, the energy density of the battery can reach 8,100 watt-hours/kg, ranking first among various battery energy densities. The Israeli company Phinergy has developed an aluminum-air test battery for electric vehicles with an energy density of over 800 Wh/kg and a cruising range of 1,600 kilometers.
▌Lithium-ion and flow batteries are expected to become mainstream technologies for energy storage batteries in the future
Lithium-ion batteries are currently the most concerned energy storage technology. According to statistics from the US Department of Energy, by the end of 2016, the United States, Japan, the European Union, and China accounted for 94% of the world’s total installed capacity, of which nearly 100 were demonstrated by electrochemical energy storage. The number of projects accounted for 53%. Among the number of electrochemical energy storage demonstration projects, lithium-ion batteries accounted for the highest proportion, reaching 48%, ranking the highest in battery energy storage. In the future, the new generation of lithium-ion battery technology will bring fundamental changes to battery safety, energy density, charging time and other indicators. It has broad applications in the fields of power grid peaking and frequency modulation, electric vehicles, commercial/home energy storage systems, etc. prospect.
Flow battery has the advantages of large capacity and low cost. It can build economical and reliable energy storage power stations above 100,000 kilowatts, providing important support for improving the flexibility of grid dispatching control and large-scale development of new energy. The construction and operation of energy storage power stations in large energy bases, central substations, load centers, and the end of the power grid can provide various auxiliary services such as peak regulation, frequency regulation, and voltage regulation, which can maintain the balance of power generation and consumption, alleviate local blockage of the grid, and cope with It plays an important role in power grid emergencies. The deployment of a large-capacity liquid flow energy storage system in the new energy power generation base can effectively smooth the fluctuation of new energy power generation output, flexibly follow the power generation plan curve, and promote new energy power generation to become the main power source.
Based on the judgments of the International Renewable Energy Agency and the International Energy Agency, lithium-ion and flow batteries will break through the technical bottleneck around 2030, and the overall performance of the battery will be fully improved, becoming the mainstream battery technology with the most large-scale commercial prospects. The proportion of energy storage battery capacity will exceed 50%, which will greatly promote the development and application of energy storage battery technology.
▌The innovation and development of a variety of energy storage battery technologies will play an important role in the new generation of power systems
With the development and wide application of various battery energy storage technologies in the future, energy storage batteries will be applied to all aspects of the power system "generation, transmission, distribution, use, and adjustment", which may change the existing power system production, transportation and use methods , To help the traditional power system to transform into a new generation of power system with "extensive interconnection, intelligent interaction, flexibility, safety and control".
On the power generation side, lithium-ion batteries and flow batteries will become important energy storage technologies to support the large-scale development of new energy, and promote new energy to become the main power source of the new generation of power systems. As of the end of 2017, the combined grid-connected capacity of wind power and photovoltaic power generation in my country reached 293 million kilowatts, accounting for 17% of all installed power sources. In the future, my country's new energy will accelerate its large-scale development. According to the national non-fossil energy development goals and carbon emission reduction goals, considering the slowdown scenario of hydropower and nuclear power installations, the total installed capacity of wind power, photovoltaic power and other new energy power generation in the country by the end of 2030 must reach at least 880 million kilowatts, which is the end of 2016 New energy power generation installed capacity is about 3.5 times, accounting for about 30% of total power installed capacity. In the future, a high proportion of new energy access will become the main feature of my country's new generation of power systems. How to manage large-scale new energy grid-connected operations needs to greatly improve the flexibility of the power system. Lithium-ion batteries and flow batteries will achieve further breakthroughs in short-term high-power output, fast response speed, etc., effectively smooth large-scale new energy generation output fluctuations, flexibly track the output curve of power generation plans, and realize new energy power plants that are observable and measurable , Controllable.
On the grid side, flow batteries are favored as large-capacity grid-level energy storage power stations, which can provide a variety of auxiliary services to the grid and enhance the flexibility and safety of grid dispatching control. Flow battery has the technical advantages of long cycle life, large capacity, fast response speed, and high safety. In the future, it is expected to replace the lithium-ion energy storage power station currently in operation and develop into a grid-level energy storage power station of 100,000 kilowatts and above. It provides various auxiliary services such as peak regulation, frequency regulation, and voltage regulation, which play a role in adjusting the imbalance of power generation and consumption and responding to grid emergencies. At the same time, the construction of large-capacity liquid energy storage power stations in areas around large energy bases, central substations, load centers, and grid terminals can give full play to the important role of energy storage power stations in different regions in alleviating local grid congestion and promoting power balance.
On the user side, lithium-ion batteries will become the mainstream technology that promotes the development of distributed small battery energy storage systems, and new batteries can be used as complementary applications for lithium-ion batteries. In the future, there will be further breakthroughs in lithium-ion battery technology. The energy density will be close to 600 watt-hours/kg, and the endurance will exceed 500 kilometers, which is about double the current rate; the charging time will be shortened to less than 30 minutes, and the service life will reach 15 years. Performance requirements for energy storage and mobile power supplies. The new battery can be combined with lithium-ion batteries to achieve integrated applications in the fields of electric vehicles and household distributed energy storage. In the future, distributed optical storage applications have great potential. Some users who have small power requirements and are not strongly dependent on the grid may choose distributed optical storage systems for independent power supply due to economic interests. User choices have already appeared in Hawaii, the United States. Distributed optical storage + grid" power supply mode.