Because the output voltage of monolithic solar cells is low, and the electrodes of unencapsulated cells are easy to fall off due to the influence of the environment, a certain number of monolithic cells must be sealed into PV modules in series and parallel to avoid battery electrodes and interconnections. The wire is corroded, and the packaging also avoids battery breakage, which facilitates outdoor installation. The quality of the packaging determines the service life and reliability of the PV module. So what is a PV module? Let's take a look together next.
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Composition of PV modules
Basic characteristics of PV modules
The PV module is composed of high-efficiency crystalline silicon solar cells, ultra-white cloth-patterned tempered glass, EVA, transparent TPT backplane, and an aluminum alloy frame. It has the characteristics of long service life and strong mechanical pressure resistance.
The structural forms of PV modules are as follows: glass shell structure, bottom box PV module, flat-panel PV module, and fully glue-sealed PV module without cover.
The output power of the PV module is equal to the output voltage multiplied by the working current. Most of the I-U curves of PV modules are measured under standard test conditions (STC). This I-U curve includes three important points: maximum power point (UMP×IMP), open-circuit voltage point (UOC), and short circuit current point (ISC).
It can be seen that the output current of PV modules is proportional to the irradiance of sunlight. The stronger the sunlight, the higher the output power of PV modules. As the irradiance of sunlight decreases, the shape of the volt-ampere characteristic curve is basically unchanged, but the short-circuit current of the PV module gradually decreases. The open-circuit voltage does not change much with the irradiance.
When the temperature of the PV module is higher than the standard operating temperature of 25°C, the efficiency of the PV module decreases, which is mainly manifested in the decrease of the open-circuit voltage. As the temperature increases, the shape of the volt-ampere characteristic curve is basically unchanged, but the entire leftward shift indicates that the open-circuit voltage decreases as the temperature increases.
When one cell in the PV module is shaded, it will affect the performance of the entire PV module. If one cell in the PV module is completely shaded, it may cause the power loss of the entire PV module as high as 75%. Of course, some PV modules are less affected by shading than this example.
In order to produce better PV modules, the manufacturer of Anhui JF Solar Technology Co., Ltd. (JF Solar) has carried out a large number of tests before leaving the factory to ensure the quality of PV modules. If you are interested in PV modules, you can contact us, our website is https://www.jf-solartech.com/. I look forward to working with you very much.