The smallest unit for photoelectric conversion is a solar cell. Its size is 4~100cm2, the working voltage is 0.45~0.50V, and the working current is 20~25mA/cm2, so it cannot be used as a power supply alone.

solar array
The smallest unit for photoelectric conversion is a solar cell. Its size is 4~100cm2, the working voltage is 0.45~0.50V, and the working current is 20~25mA/cm2, so it cannot be used as a power supply alone. In a photovoltaic power generation system, solar cell monomers need to be connected in series, parallel and packaged to form a solar cell module. Its power can be from a few watts to hundreds of watts, and it can be used as a power supply alone. The solar cell array is to install the solar cell components on the bracket after being connected in series and parallel. It can output hundreds of watts, several kilowatts or even more power, and it is the electric energy generator of the photovoltaic power generation system. 
The frame of the solar cell phalanx should be as strong as possible and have sufficient rigidity. At the same time, the weight should be light. When installing a solar cell array, use a metal bracket with a certain strength and is conducive to fixing and supporting. In deserts, coastal areas, polar regions, high mountains, tuyere and other areas where the geographical environment is relatively harsh or the climatic conditions are relatively complex, the solar cell array Some additional measures should be taken for the support to be able to bear the additional weight of strong wind and ice and snow deposits, and avoid collapse due to natural, man-made and some large animal damage.  
Generally speaking, there are three installation forms of solar cell arrays: on the ground, on columns, and on the roof. Which installation form to use will be affected by some specific factors, such as the size of the available space, the size of the square array, lighting conditions, wind load, visual effects, difficulty of installation, damage and theft, etc. Among the several installation forms mentioned above, the first choice is to install on the ground because of its simplicity and ease of use. The difficulty of installing on the column is affected by the height of the battery panel from the ground. The difficulty of installing on the roof depends on whether the roof is steep or not. Working on a relatively steep roof is not only time-consuming and laborious, but also very dangerous. During the installation process, it is especially necessary to avoid damage to the electrical performance of the solar panel. For this reason, the surface of the solar panel should be covered to reduce the probability of damage. It is also possible to build a fence around the photovoltaic power station to prevent animals from approaching the equipment. This ensures system security. At the same time, the installed solar panels should face the sun at noon, not the direction of the compass, which is stated in the relevant materials. In addition, the inclination angle between the solar panel and the horizontal plane should be greater than 10°. In this way, the rainwater falling on the solar panel can quickly slide down to the ground, thereby keeping the surface of the solar panel clean. 
There are many kinds of solar cell components, which can be divided according to the type of solar cells: monocrystalline silicon components, polycrystalline silicon components, gallium arsenide components, amorphous silicon thin film battery components, etc., of which crystalline silicon (including monocrystalline silicon and multi-product silicon) Solar cell modules account for about 80% to 90% of the market. The packaging materials and processes of crystalline silicon are also different, which are mainly divided into epoxy resin sealing, laminated silicon packaging and so on. At present, the most widely used method is vacuum lamination packaging, which is suitable for industrial packaging of large-area cells. 
solar battery
The independent photovoltaic power generation system relies on the battery to store excess electric energy, so the battery plays an important role in the independent photovoltaic power generation system. With the decline in the selling price of solar cell components, the proportion of storage battery costs in the total system investment will gradually increase. In addition, in the operation of an independent photovoltaic power generation system, the normal operation of the system will be affected due to battery failure. Therefore, when designing the system, it is very important for the normal operation of the independent solar photovoltaic power generation system to select the appropriate battery type, determine the appropriate battery capacity, accurately implement installation, operation, and meticulous maintenance. 
At present, there are many types of batteries commonly used in photovoltaic systems, among which the most widely used are ordinary lead-acid batteries, alkaline nickel-chromium batteries and lead-acid maintenance-free batteries. Ordinary lead-acid batteries are mainly used in some low-end occasions with maintenance capabilities due to their large environmental pollution and certain maintenance requirements. The advantage of alkaline nickel-chromium storage battery is that it has good low temperature, overcharge and overdischarge performance, but the disadvantage is that the price is relatively high, and it is generally used in more special occasions. Lead-acid maintenance-free batteries are the most widely used batteries in China at this stage. Its maintenance-free characteristics make its maintenance simple and convenient, reliable in performance, and less polluting to the environment. It is very suitable for solar power generation that requires high performance and reliability. systems, such as unattended workstations, etc. 
Power Electronic Converters (Inverters)
The solar cell array generates direct current under sunlight, but most of the common loads in daily life need to be powered by alternating current, such as fluorescent lamps, televisions, refrigerators, electric fans, air conditioners, etc., as well as most power machinery. Therefore, a device that converts DC to AC is needed, which is an inverter. The inverter in the photovoltaic power generation system is a variable current circuit, whose function is to convert the direct current generated by the solar cell array into alternating current with various required frequencies and voltage values. Inverters can be divided into two types: passive and active. Passive inverter means that DC power is directly supplied to the load through inversion. Active inverter means that DC power is supplied to AC power through inversion. The necessity of DC to AC is also reflected in the fact that when the power supply system needs to increase or decrease the voltage, the AC system only needs to add a transformer, while the technology and devices in the DC system are much more complicated. Therefore, except for special users, inverters are required in photovoltaic power generation systems. In addition, the inverter also has the function of automatic voltage regulation or manual voltage regulation, which can improve the power supply quality of the photovoltaic power generation system. Obviously, the inverter is an indispensable and important supporting equipment in the photovoltaic power generation system.