Traditional fossil energy belongs to non-renewable energy, with the development of industry for energy further increasing. People vigorously developed battery energy storage technology to ensure the continuity and stability of energy power supply. Renewable energy is characterized by obvious intermittency and volatility. Unstable power input easily impacts the power grid, and in severe cases, it will cause grid accidents.
Therefore, vigorously developing battery energy storage technology can not only ensure the continuity and stability of renewable energy power supply, but also improve the utilization rate of renewable energy through peak shaving and valley filling, and reduce the waste of resources such as abandoning wind and light.
1. Battery energy storage technology in the power system
Battery energy storage technology has been widely used in power systems due to its advantages of high storage capacity, high power, stable output, and not limited by geographical environment and terrain environment.
The complete power system can be divided into three parts: power generation side, power grid side and user side.
● Power generation side
The application of battery energy storage technology is mainly divided into three directions. That is, new energy grid integration, power auxiliary services and microgrids.
- New energy grid integration
New energy is connected to the grid. Since the power generation of renewable energy such as wind power and photovoltaics fluctuates with changes in the environment, the unstable power generation characteristics of these new energy sources will have a non-negligible impact on the security of the power grid.
The battery energy storage system has the characteristics of fast response speed and strong ability to track load changes. It also improves the stability, controllability and planability of the power output.
- Power auxiliary services
The selection of high-power battery energy storage technology can be used for frequency and voltage regulation to meet the changing power demand of users and reduce power generation costs.
- Microgrid field
Battery energy storage technology can also increase revenue by taking advantage of peak-to-valley electricity price differences.
● Grid side
Battery energy storage technology is mainly used for peak shaving and valley filling, solving problems such as intelligent power supply and distributed power supply. Because the power generation capacity of power plants usually cannot be easily changed, it is easy to waste power generation when electricity consumption is low.
And it is easy to risk power outages due to too large loads at peak electricity consumption.Through the application of large-scale battery energy storage technology, the load ratio of the grid can be improved and energy can be saved. In addition to peak shaving and valley filling, the volume design of battery energy storage devices is flexible and not limited by geographical environment.
It can be applied to villages, pastoral areas, mountainous areas and other environments where users are scattered and the terrain is complex, which is suitable for distributed power supply and reduces the cost of transmission and distribution.
● User side
The application scenarios of battery energy storage technology are very extensive. In addition to providing energy sources for mobile phones, computers, electric vehicles and other power terminals, it can also be widely used as a backup power source in hospitals, factories, communication base stations, data centers and other places to improve disaster response capacity.
Also, through battery energy storage technology, power is stored during low electricity consumption and used at peak times to ensure power security and reduce electricity costs. Thus, numerous home energy storage battery companies are working on this technique
2. The development of battery energy storage technology
In order to meet the needs of the power system, the large-scale application of battery energy storage technology needs to meet three basic requirements: high safety, high cost performance, and low pollution.
At present, the most mature commercial application is lithium-ion batteries. As the market demand for high-performance energy storage devices continues to increase, these emerging energy storage technologies will accelerate the transformation from basic research to engineering applications.
● Lithium ion battery
The principle of lithium ion battery energy storage technology is that lithium ions are embedded and deintercalated between the positive and negative electrodes. The cathode material of lithium ion batteries directly determines the capacity of the battery and is the most critical material.
Lithium ion batteries are mainly divided into lithium cobalt oxide batteries, lithium manganate batteries, nickel-cobalt-manganese ternary lithium batteries, and lifepo4 battery according to different cathode materials.
● Lithium cobalt oxide battery
Lithium cobalt oxide is used as the cathode material, which has a high specific capacity and high volumetric energy density, but the cost is higher due to the need for cobalt in the material. At present, lithium cobalt oxide batteries are mainly used in consumer electronics such as mobile phones and laptops.
● Lithium manganate battery
Lithium cobalt oxide materials are more stable and have better safety performance while achieving high charge and discharge rates. Lithium manganate does not contain cobalt and is cheaper. Lithium manganate batteries have a low cost and are currently widely used in low-speed electric vehicles and plug-in hybrid vehicles.
● Ternary lithium battery
Combining the advantages of lithium nickelate, lithium cobalt oxide and lithium manganate, it has the advantages of high specific capacity, good cycle performance and high working voltage. Ternary lithium batteries have developed rapidly and have begun to replace lithium cobalt oxide batteries in the field of consumer electronics.
● Lithium iron phosphate battery
It has the advantages of high working voltage, long cycle life, good safety performance and low price, and is widely used in various energy storage scenarios. The application of lithium iron phosphate batteries in the field of power batteries has grown rapidly and entered a period of rapid development.
3. Application of battery energy storage technology
The commercial application of battery energy storage technology can be divided into three main areas: energy storage, power batteries and consumer electronics. In different application areas, the requirements for energy storage technology are also different.
● Energy storage field
In the field of energy storage, the main application scenarios of battery energy storage technology lie in the energy storage of renewable energy sources such as wind and solar.
Due to huge power generation, the cost of battery energy storage technology is very high. The earliest large-scale battery energy storage device used in the field of energy storage is lead-acid batteries. With the cost of lithium-ion batteries falling in recent years, the dominance of lead-acid batteries in the field of energy storage has been gradually replaced by lithium iron phosphate batteries.
● Power battery field
Due to the high requirements of passenger cars for battery energy density, power density and safety performance, lithium-ion batteries are currently widely used in the field of power batteries.
With the widespread promotion of battery energy storage technology, the frequency of lithium-ion battery fire and explosion accidents has also increased. Further improving the stability and safety of batteries is still the focus of future battery energy storage technology development.
● Consumer electronics
The consumer electronics field mainly includes notebook computers, tablet computers, smart phones, wearable devices, smart speakers and other fields. With the increasing demands of the market for the volume, endurance and fast charging capacity of electronic products, battery energy storage devices need to have the characteristics of small size, high energy and power density.
Consumer lithium-ion batteries started earlier in the lithium-ion battery industry, and after more than ten years of development, the performance of lithium-ion batteries has been continuously improved, and has completely replaced the earliest nickel-cadmium, nickel-metal hydride batteries.
After years of development, battery energy storage technology has made great progress in terms of performance, cost, and application range.
A variety of battery energy storage technologies represented by lithium-ion batteries have completed commercialization and begun to develop in the direction of scale. The implementation and application of these advanced battery energy storage technology will play a major role in the development of battery energy storage technology.