1. How does the illuminance of light affect the performance of photovoltaic cells?
Photovoltaic cell is a device that converts solar radiation light energy into electrical energy. Its output power is directly related to the illuminance of light. Under the condition of constant temperature, the output current of photovoltaic cell is proportional to the intensity of light illuminance. , the open circuit voltage increases slowly with the illuminance of the light, the peak output power increases almost proportional to the illuminance of the light, and the fill factor is hardly affected by the illuminance of the light, and remains basically unchanged under different illuminances.
2. How does temperature affect the performance of photovoltaic cells?
The main parameters of photovoltaic cell materials, such as intrinsic carrier concentration, diffusion length, and absorption coefficient are all functions of temperature. In particular, the output power of photovoltaic cells is closely related to temperature. Under the condition of constant illumination, when the temperature of photovoltaic cells increases, the output power will decrease. When the temperature of the photovoltaic cell rises, the output current will increase slightly, and the open circuit voltage will gradually decrease with the increase of temperature, and the peak output power will also decrease.
Since temperature has an effect on the output efficiency of photovoltaic cells, it is suitable for use in cold areas, but not suitable for use in hot areas. In order to reduce the adverse effect of temperature on photovoltaic cells, when using in hot areas, certain measures should be taken to prevent the temperature of photovoltaic panels from being too high.
3. What is the effect of cell thickness on the performance of photovoltaic cells?
Improving the photoelectric conversion efficiency and reducing the cost of photovoltaic cells is the main direction of photovoltaic cell development. Reducing the thickness of photovoltaic cells can reduce the amount of materials used, thereby reducing the cost of photovoltaic cells. Therefore, reducing the thickness of photovoltaic cells has become the goal pursued by the current photovoltaic industry.
A thick photovoltaic cell wastes materials, but if it is too thin, it will affect the short-circuit current density, open-circuit voltage and photoelectric efficiency of the photovoltaic cell, thereby affecting the quality of the photovoltaic cell. In order to find a suitable thickness, people have done a lot of experiments on polycrystalline silicon photovoltaic cells. It was found that when the thickness of polycrystalline silicon wafers is greater than 200 μm, the relationship between the efficiency of photovoltaic cells and the thickness of silicon wafers is independent of each other. That is, the efficiency of photovoltaic cells is not affected by thickness variations. When the thickness of the polycrystalline silicon wafer is less than 200 μm, the absorption of the incident light by the substrate begins to decrease, so the short-circuit current density of the photovoltaic cell is affected; when the thickness of the silicon wafer is very low, some photons will pass through the silicon wafer and cannot be absorbed, so The photoelectric conversion efficiency of photovoltaic cells continues to decline.
As a result, it is widely believed that the optimum thickness limit for polycrystalline silicon photovoltaic cells is 200 μm.
This optimal thickness limit is only for polycrystalline silicon photovoltaic cells, and is invalid for single crystal silicon or other photovoltaic cells. As for the optimal thickness limit of other photovoltaic cells, the same method should be used to find out. Knowing the optimal thickness limit is extremely beneficial for photovoltaic cell production.