The principle and application of lithium battery energy storage

What is lithium battery energy storage

Lithium battery energy storage is important, referring to the storage of electrical energy. The stored energy can be used as emergency energy storage when grid load is low and energy output when grid load is high. Lithium-ion batteries refer to batteries made of lithium-containing compounds that rely mainly on lithium ions to move between anode and cathode to work.

Lithium ion batteries, in addition to powering lithium batteries, can also be used as energy storage batteries, because the safety of lithium ion batteries is very good. Most energy storage power stations choose lithium ion iron phosphate batteries as energy storage batteries.

Lithium battery energy storage is currently the most common energy storage technology on the market, and is widely used in various personal electronic products, mobile devices, and even the lithium solar batteries for solar panels.

Usually, we refer to lithium batteries as lithium-ion batteries, which are generally divided into energy storage and power lithium batteries according to their use. Lithium battery energy storage is used in photovoltaics or UPS. Its internal resistance is relatively large, charging and discharging speed is slow, generally 0.5-1C.

Power batteries are generally used in electric vehicles, small internal resistance, fast charging and discharging speed, generally can reach 3-5C, and the price is about 1.5 times more expensive than energy storage batteries.

The principle of lithium battery energy storage

Lithium-ion batteries rely mainly on lithium ions to move between  cathode and anode. In the charging and discharging process, there are only lithium ions; there is no lithium metal. Compared with other batteries, lithium batteries have the advantages :

• High energy density
• Long cycle life
• Low self-discharge rate,
• High energy conversion rate
• Fast charge and discharge

Moreover, lithium battery energy storage power stations are widely used in new power stations. The  lithium ion battery applications have relatively few  in traditional power stations. Due to voltage instability and uncertain timing of wind and solar power generation, it is more beneficial to use energy storage power stations as power relays for healthy grid operations.

At present, the hot lithium material is also worth noting. It can replace graphite as an anode material. Although the energy density is not high, lithium titanate can enable the battery to achieve high charge and discharge rates, has excellent safety performance, and has a long cycle life.

The application of lithium battery energy storage

It is understood that lithium battery application scenarios on the power side, user side, and grid side of energy storage are lithium battery energy storage applications on the power generation side.

● Power side

Key points include photovoltaic storage power station, wind storage power station, AGC frequency regulation power station;

● User side

The key points of lithium battery energy storage on the user side include photovoltaic storage charging stations, home energy storage, backup power supply, etc.;

● Grid side

Grid lithium battery energy storage is used in scenarios such as substation energy storage, virtual power plants, and peak shaving/frequency regulation.

So far, for different fields and different needs, people have proposed and developed a variety of energy storage technologies to meet the application. Lithium battery energy storage is currently the most feasible technical route.

From the perspective of the economy of lithium battery energy storage, lithium ion batteries have a strong competitiveness. Sodium sulfate batteries and vanadium redox flow batteries have not been industrialized, and supply channels are limited and expensive.

From the point of view of operation and maintenance costs, sodium sulfide batteries need continuous heating, vanadium flow batteries need to pump fluid control, which increases the cost of operation, and lithium ion batteries require almost no maintenance.

The future development of lithium battery energy storage

Lithium battery energy storage is a very important energy storage technology, widely used in portable electronic devices and EV. The cost of global lithium battery energy storage continues to decline. However, future energy storage methods will shift from lithium-ion batteries to richer, innovative solutions.

Lithium battery energy storage, as an emerging application scenario, has also gradually received attention. Energy storage is one of the important ways to solve the intermittent volatility of new energy, wind power and photovoltaics.

Application of energy storage power station

In the practical application of lithium battery energy storage, renewable energy grid, user side, grid side, and auxiliary services are the four most important areas.

● Emergency power supply car

Lithium battery energy storage emergency power supply vehicle is composed of lithium-ion battery pack, inverter, battery management system, etc., and the inverter directly converts the battery into single-phase and three-phase alternating current.

Usually, you only need to freely choose the charging period to charge the battery pack, and when the battery pack is fully charged, it can be called at any time within one year, and there is no need to float charge. 

● Fixed power station

Lithium battery energy storage fixed power station is composed of a lithium ion battery pack and BMS, PCS, EMS, and auxiliary systems and installed in the container power station type energy storage system.

Because lithium-ion batteries have a small self-discharge, they do not need to be kept in a floating charge state for a long time. A lithium battery energy storage power station combined with a new energy generation system can become an independent distributed microgrid power source.

It is suitable for providing reliable power in areas without electricity and the top 10 energy storage battery manufacturers in China have worked on this filed for years. Lithium battery energy storage power stations can be combined with distributed or centralized new energy generation.

It is one of the most effective ways to solve the problem of connecting new energy generation grids,  with the increasing scale of new energy generation and the continuous development of lithium ion battery energy storage technology.

● Communication backup power

The important market for communication backup power consists of two parts. One is the lithium battery energy storage composition of the new base stations. Part of this is the replacement of obsolete base station batteries, which constitutes the bulk of the market every year.

The construction of 50,000–100,000 base stations every year will bring 1.2–2.4 GWh of lithium battery demand, and a total of about 10 GWh of battery demand per year will be met by ferrolithium-ion batteries and echelon utilization batteries.

Conclusion

Lithium battery energy storage has the advantages of high efficiency, application flexibility, and fast response speed, and it gradually occupies an increasingly important position in the power energy storage market.

Lithium ion batteries can be applied to power quality, reliability control, backup power, peak shaving, energy management, renewable energy storage, etc.