1 The working principle of energy storage batteries
The working principle of energy storage batteries is based on electrochemical reactions. Taking lithium-ion batteries as an example, during charging, lithium ions are released from the positive electrode, embedded in the negative electrode through the electrolyte, and the negative electrode is in a lithium rich state; When discharging, it is the opposite. This reversible electrochemical reaction process enables the storage and release of electrical energy.
2 Classification of energy storage batteries
Energy storage batteries can be classified into various types based on their energy storage principles and technical characteristics, mainly including:
Lead acid battery:
Features: The electrode is made of lead and its oxides, and the electrolyte is sulfuric acid solution. It has the advantages of safe sealing, gas release system, simple maintenance, long service life, stable quality, and high reliability. But the disadvantage is that lead pollution is significant and the energy density is low.
Application: Widely used in UPS power supply, solar street lights, security systems and other fields.
Nickel based batteries:
Characteristics: Represented by nickel hydrogen batteries, the positive electrode active material is Ni (OH) 2, the negative electrode active material is metal hydride, and the electrolyte is potassium hydroxide solution. It has the advantages of high energy density, fast charging and discharging speed, light weight, long lifespan, and no environmental pollution. However, there are drawbacks such as slight memory effects, multiple management issues, and the tendency to cause melting of single-cell battery separators.
Application: Suitable for fields such as hybrid vehicles and electric tools.
Lithium based batteries:
Features: Lithium ion batteries use lithium metal or lithium alloy as the negative electrode material and use non-aqueous electrolyte solutions. It has the advantages of high energy density, long lifespan, light weight, and strong adaptability. But the safety is poor, prone to explosion, and the cost is high.
Application: Widely used in fields such as electric vehicles, portable electronic devices, energy storage power stations, etc.
Flow battery:
Features: Suitable for fixed large-scale energy storage, with advantages such as independent design of power and energy storage capacity, high efficiency, long lifespan, deep discharge capability, and environmental friendliness. But the energy density is relatively low.
Application: Mainly used in large-scale energy storage power stations, power grid peak shaving and other fields.
Sodium sulfur battery:
Features: Using sodium metal as the negative electrode and sulfur as the positive electrode, it has the advantages of high specific energy, no self discharge phenomenon, high discharge efficiency, and long service life. But it needs to work at high temperatures and the cost is relatively high.
Application: Suitable for specific high-temperature energy storage scenarios.
3 Application scenarios of energy storage batteries
The application scenarios of energy storage batteries are wide and diverse, mainly including the following aspects:
1. Renewable energy grid connection
Energy storage batteries play a crucial role in the integration of renewable energy sources such as solar and wind power into the grid. These energy sources have intermittency and volatility, and energy storage batteries can smooth out their power output fluctuations, reduce the impact on the power system, and improve the ability of power stations to track planned output. For example, in wind and photovoltaic power generation systems, energy storage batteries can absorb excess electricity and release it when needed, ensuring the stable operation of the power grid.
2. Grid auxiliary services
Energy storage batteries play an important role in grid auxiliary services, including capacity based and power based services. Capacity based services such as grid peak shaving, load following, and black start can cope with changes in grid load and unexpected situations. In terms of power grid peak shaving, energy storage batteries can respond to dispatch instructions in a timely and reliable manner based on changes in power sources and loads, and adjust their output levels according to the instructions. In addition, energy storage batteries can improve the frequency regulation capability of the power grid and reduce the losses caused by frequent switching of traditional frequency regulation power sources.
3. Power grid transmission and distribution
In the field of power grid transmission and distribution, energy storage batteries can improve the quality and reliability of power distribution. When there is a fault in the distribution network, energy storage batteries can serve as a backup power source to continuously supply power to users, ensuring the continuity of power supply. At the same time, energy storage batteries can also be used as controllable power sources to control the power quality of the distribution network, eliminate voltage dips, harmonics and other problems, and improve power quality.
4. Distributed and microgrid
In distributed and microgrid systems, energy storage batteries are an indispensable component. The microgrid system requires energy storage devices to provide short-term uninterrupted power supply in the event of off grid and distributed power sources being unable to provide power, meet microgrid peak shaving requirements, improve microgrid power quality, complete microgrid system black start, and balance the output of intermittent and fluctuating power sources. Energy storage battery systems have the characteristics of dynamically absorbing energy and releasing it in a timely manner, which can improve power quality, stabilize network operation, optimize system configuration, and ensure the safe and stable operation of microgrids.
5. User side energy storage
User side energy storage mainly includes peak shaving and valley filling in industry and commerce, as well as demand side response. The combination of energy storage batteries and power electronics technology can provide users with reliable power sources, improve power quality, and save costs for users by utilizing the price difference between peak and valley electricity prices. For example, in the industrial and commercial sector, energy storage batteries can be charged during low electricity prices and discharged during high electricity prices, reducing the electricity costs of enterprises.
6. Electric vehicle field
With the rapid development of the new energy vehicle industry, the application of energy storage batteries in the field of electric vehicles is becoming increasingly widespread. The power battery is the core component of electric vehicles, which directly affects the vehicle's range and performance. The development of energy storage battery technology has significantly increased the range of electric vehicles, while reducing energy consumption and charging time.
7. Home energy storage
Home energy storage is another important area of application for energy storage batteries. Efficient and convenient energy storage solutions such as wall mounted lithium batteries can effectively store and manage household electricity resources, improve energy utilization efficiency, and reduce electricity costs. In the combination of renewable energy equipment such as solar photovoltaic systems and wind power generation systems, household energy storage batteries can provide users with stable and reliable power supply, and provide emergency power guarantee in case of power outages or power failures in the grid.
4 Energy storage batteries have multiple specific roles in distributed energy
1. The volatility of smooth distributed power generation
Stable output: Distributed energy sources such as renewable energy sources like solar and wind have intermittent and fluctuating power generation. Energy storage batteries can store the intermittently generated electrical energy and release it when needed, thereby smoothing out the fluctuations of distributed power generation and maintaining stable output of the power system.
Reduce grid impact: By regulating energy storage batteries, the impact of distributed energy systems on the grid can be reduced, avoiding the grid from being affected by sudden increases in load or decreases in power generation.
2. Improve energy utilization efficiency
Supply and demand matching: Energy storage batteries can store electricity during low load periods and release electricity during peak load periods based on the actual demand of the power system, thereby achieving dynamic matching between supply and demand and improving energy utilization efficiency.
Multi energy allocation: In distributed energy systems, energy storage batteries can be combined and allocated with multiple energy sources to form complex systems such as microgrids, further optimizing energy utilization structures and improving overall energy efficiency.
3. Enhance the stability and reliability of the power grid
Backup power supply: In the event of a power grid failure or outage, energy storage batteries can serve as a backup power source to provide continuous and stable power supply for critical loads, ensuring the stability and reliability of the power grid.
Improving resilience: Energy storage batteries can serve as a rotating backup for the power grid, alleviating fluctuations caused by peak and off peak electricity consumption, reducing the pressure of power grid regulation and scheduling, and improving power utilization efficiency.
4. Promote the consumption of renewable energy
Energy storage regulation: Energy storage batteries can store excess electricity generated by renewable energy generation and release it when needed, thereby increasing the consumption of renewable energy and reducing wind and solar power curtailment rates.
Balancing supply and demand: By regulating energy storage batteries, the supply and demand relationship between distributed energy systems and the power grid can be balanced, improving the grid connection capability and utilization efficiency of renewable energy.
5. Economic and environmental benefits
Reduce electricity costs: Energy storage batteries can be charged during low electricity prices and discharged during high electricity prices, thereby reducing users' electricity expenses.
Reducing carbon emissions: By promoting the consumption of renewable energy and reducing the use of fossil fuels, energy storage batteries can help reduce carbon emissions and improve environmental quality.
