The refractive index is 2.30, surface passivation is best, and body passivation is poor; the refractive index is 2.17, the surface passivation is good, and the body passivation is best with refractive. index less than 2.05. The passivation is poor and the anti-reflective effect is good.
The refractive index of silicon-based solar cells mainly involves two aspects. One is the film thickness and refractive index of the blue film on the solar cell, and the other is the packaging of the components. . The film thickness and refractive index of the glass material used, including the EVA used, etc. If these are the parameters of the blue film produced by pecvd in the crystalline silicon solar process, in theory, increasing the refractive index will improve the efficiency, especially for multilayer films and coating methods with aprogressively increasing refractive index. there are other factors in the actual application. If the refractive index is too high, it is easy to cause the coating to be incorrectly colored, that is, the blue color appears hazy. It is difficult to sell cells with such an appearance. . Regarding the problem of back plating, the main reason is that the current aluminum paste is difficult to burn through silicon nitride, which will cause the back field of the cell to fall and affect the reliability of the cell, it is necessary therefore avoid it. .
The photovoltaic film is sandwiched between the upper and lower parts of the photovoltaic cell. A cell must be equipped with two pieces of photovoltaic film. There are three types of adhesive films, EVA, POE and EPE (EVA+POE mixture); the biggest difference between them is that the first is cheaper than the second and the performance of the first sare worse than those of the second, which is a problem. good explanation of the principle that you get what you pay for. EVA film is currently the main market. The photovoltaic adhesive film encapsulates and protects solar cell components, improves the photoelectric conversion efficiency of components, and extends the service life of components. Since the packaging process of photovoltaic modules is irreversible and the lifespan of battery modules should be more than 25 years, once the adhesive film of the battery module starts to turn yellow and crack, the battery will easily break down and therefore be scrapped. , although the absolute value of the adhesive film is not high, but it plays an important role in the quality and service life of photovoltaic modules.