At present, DC fast charging stations are the main charging method for electric vehicles. Their 

output power is small and the charging time is too long, which makes it inconvenient for users 

to charge and they have to wait in line for charging, which seriously affects the user experience. 

In order to comprehensively improve the charging efficiency, it is necessary to introduce 

photovoltaic energy storage systems in the construction of DC fast charging stations to reduce 

the operating costs of charging infrastructure.

1 Working principle of photovoltaic energy storage system

Solar energy, as a renewable energy source, can be reused through photovoltaic energy storage 

systems. Photovoltaic storage systems convert solar energy into electrical energy through 

photovoltaic panels. Photovoltaic panels are composed of multiple photovoltaic cells, and most 

of these cells are made of semiconductor materials (silicon). Once light shines on the photovoltaic 

cell, photons interact with the electrons in the material, which in turn causes the electrons to 

obtain the corresponding energy, jump to the conductor band, and continuously generate a 

certain amount of current, thereby converting light energy into electrical energy.

Since solar energy is an indirect energy source, it can only generate electrical energy during the day. 

In order to achieve a continuous supply of energy, the photovoltaic energy storage system needs to 

store the excess electrical energy generated during the day for use at night or on cloudy days. Among 

them, the common energy storage method is to store energy through battery packs, convert electrical 

energy into chemical energy through chemical reactions, and then convert chemical energy into 

electrical energy output when needed. Commonly used battery packs are lead-acid, lithium-ion 

batteries, etc. Most of these battery packs have advantages such as long life and low self-discharge 

rate, which can meet the diverse needs of photovoltaic energy storage systems.

2 Practical application of photovoltaic energy storage system in DC fast charging station

2.1 Provide stable power supply for DC fast charging station

The application of photovoltaic energy storage system in DC fast charging station can store more solar 

energy, and ensure that charging piles can stably supply electricity in the case of insufficient light, 

further reduce excessive dependence on the power grid, and promote sustainable development and 

improve energy efficiency. The photovoltaic energy storage system uses solar panels to convert sunlight 

into DC power corresponding to the DC fast charging station, and uses inverters to convert the 

remaining DC power into AC power, which is then stored in the battery pack to provide power for the 

DC fast charging station in the case of insufficient light, thereby storing and utilizing excess solar power. 

In addition, the photovoltaic energy storage system will store electricity and supply it to the DC fast 

charging station to achieve stable DC power output, thereby ensuring that the charging station can still 

charge quickly during periods of no sunlight or weak sunlight, improving the user experience and 

providing stable and reliable power support for the DC fast charging station. The DC fast charging 

station uses the photovoltaic energy storage system to convert solar energy into electricity and store 

it in a timely manner, without relying on traditional coal-fired, fuel-fired and other power generation 

methods, thereby reducing dependence on the power grid, reducing the power grid load, and 

implementing the development of green and sustainable energy supply.

2.2 Optimize the charging process and improve charging efficiency

With the widespread application of electric vehicles, the demand for DC fast charging stations is growing. 

The traditional charging method has the problems of large energy loss and low charging efficiency. 

Therefore, it is necessary to introduce the photovoltaic energy storage system into the DC fast charging 

station, and realize the optimal scheduling and management of energy under the optimization control 

of the intelligent charging management system, and continuously improve the charging efficiency of 

the DC fast charging station.

The introduction of the intelligent charging management system is the basis for optimizing and 

improving the charging process of the DC fast charging station. The system can comprehensively 

monitor the key parameters of DC fast charging stations, such as load, energy input and vehicle 

demand, and conduct intelligent scheduling based on this, improve charging efficiency and reduce 

energy loss. In this process, the output power of the photovoltaic energy storage system can be 

matched with the load demand by mastering the load situation and power demand of the charging 

station, so as to maximize the use of renewable energy power supply and reduce the proportion of 

traditional power. In addition, the intelligent charging management system can reasonably allocate 

resources, shorten charging time and improve charging efficiency by analyzing the battery status, 

charging speed and charging demand of different vehicles. For example: for vehicles with low power, 

the intelligent charging management system can adjust the charging priority so that it can charge as 

soon as possible to meet the urgent needs of users; for vehicles with sufficient power, the intelligent 

charging management system can appropriately reduce the charging power to reduce energy loss.

2.3 Transmitting excess power and implementing the goal of two-way power flow

In DC fast charging stations, the application of photovoltaic energy storage systems can achieve two 

important functions.

On the one hand, when the charging station is not in peak hours, the photovoltaic energy storage 

system needs to use solar energy to generate and store more power and transmit it to the power 

grid to avoid power waste, provide additional power resources for the power grid and reduce the 

load pressure of the power grid.

On the other hand, during the peak load period of the power grid, due to the increase in people's 

electricity demand, the power grid also needs to provide more electricity. In this link, the photovoltaic 

energy storage system needs to release the stored electricity to provide additional electricity to the 

power grid, thereby alleviating the pressure on the power grid and ensuring the stability of the power 

supply. At the same time, in addition to being directly used in charging stations, photovoltaic energy 

storage systems can also be combined with other energy systems to form a microgrid system. Among 

them, the microgrid system achieves energy complementarity and balance by combining different 

forms of renewable energy systems such as photovoltaic energy storage systems, wind energy systems, 

and battery energy storage systems.

3 The role of photovoltaic energy storage systems in the development of charging infrastructure

With the trend of full popularization of electric vehicles and the gradual reduction of renewable energy, 

the development of charging infrastructure technology is extremely important. In this process, 

photovoltaic energy storage systems use solar energy to generate electricity and store excess electricity 

to provide reliable, clean and continuous energy for charging infrastructure. The role of photovoltaic 

energy storage systems in the development of charging infrastructure is specifically manifested in four 

aspects.

First, it provides a reliable source of electricity. Traditional energy supply systems are often affected by 

unstable power supply, while photovoltaic energy storage systems can use solar energy to provide stable 

and reliable electricity for charging infrastructure. Whether in cities or remote areas, photovoltaic energy 

storage systems can provide sufficient power for charging infrastructure to meet the normal charging 

needs of electric vehicles.

Second, reduce excessive dependence on traditional energy. Traditional energy production methods will 

not only cause certain environmental pollution, but also lead to the gradual depletion of limited resources. 

The rational use of photovoltaic energy storage systems can effectively reduce dependence on traditional 

energy, making charging infrastructure more environmentally friendly and sustainable. At the same time, 

through self-produced and self-used photovoltaic energy, charging infrastructure can operate more 

independently and flexibly, reducing dependence on external energy supply.

Third, promote social and economic development. The construction of photovoltaic energy storage systems 

will drive the development of new energy industries, create employment opportunities, and increase 

employment rates. At the same time, charging infrastructure using photovoltaic energy storage systems 

can also attract more investment and tourists, and promote local tourism and business development. The 

promotion and application of photovoltaic energy storage systems will bring huge impetus to the 

sustainable development of social economy.

Fourth, accelerate energy transformation and reduce carbon emissions. Photovoltaic energy storage systems 

use renewable solar energy to provide continuous clean energy for DC fast charging stations, which is 

environmentally friendly. Through the large-scale application of photovoltaic energy storage systems, we can 

continuously reduce dependence on traditional energy, reduce carbon emissions, and achieve green energy 

transformation.