What are the differences in the impact of light intensity on different types of photovoltaic modules?

The influence of light intensity on different types of photovoltaic modules is mainly reflected in aspects such as power generation efficiency, photo-induced attenuation and temperature effect, as follows:

Power generation efficiency

Monocrystalline silicon photovoltaic modules: When the light intensity is low, monocrystalline silicon modules can maintain a high photoelectric conversion efficiency because of their regular crystal structure and strong ability to absorb and convert light. With the increase of light intensity, its output power grows approximately linearly. However, when the light intensity exceeds a certain value, due to the influence of factors such as the internal resistance of the battery, the efficiency growth will gradually slow down. After approaching the limit efficiency, it will no longer increase significantly.

Polycrystalline silicon photovoltaic modules: Polycrystalline silicon modules have defects such as grain boundaries inside. Under low light intensity, their ability to absorb and convert light is slightly inferior to that of monocrystalline silicon modules. However, with the increase of light intensity, its output power can also rise relatively stably, and a relatively high conversion efficiency can be achieved under medium light intensity. When the light intensity is too high, its efficiency will also reach saturation, but the saturation point is generally slightly lower than that of monocrystalline silicon modules.

Thin-film photovoltaic modules: Thin-film modules usually have better adaptability to low-light environments and can achieve high photoelectric conversion efficiency under low light intensity. They can generate electricity by utilizing scattered light and light from cloudy days. However, due to its thin light-absorbing layer, under high light intensity, its photogenerated carriers tend to reach saturation, the output power grows slowly, and the conversion efficiency is relatively lower than that of monocrystalline silicon and polycrystalline silicon modules.

Photoinduced attenuation

Monocrystalline silicon photovoltaic modules: Monocrystalline silicon modules have a certain degree of photo-induced attenuation. This is mainly because light can cause changes in impurities and defects in the silicon wafers, reducing the minority carrier lifetime and thus resulting in a certain degree of decrease in the output power of the module in the initial stage. However, after a period of exposure to light, the attenuation will gradually stabilize.

Polycrystalline silicon photovoltaic modules: The photo-induced attenuation of polycrystalline silicon modules is relatively more complex than that of monocrystalline silicon modules. Besides being related to impurities and defects in the silicon wafers, it is also associated with factors such as grain boundaries. The initial light-induced attenuation amplitude may be relatively large, but it will gradually stabilize after a certain period of exposure to light. The long-term attenuation degree is generally slightly greater than that of monocrystalline silicon modules.

Thin-film photovoltaic modules: The light-induced attenuation of thin-film modules made of different materials varies greatly. For instance, the photo-induced attenuation of amorphous silicon thin-film modules is relatively severe. This is because light exposure increases the defects in the amorphous silicon structure, leading to a decline in photoelectric performance. The photoinduced attenuation of thin-film modules such as cadmium telluride (CdTe) and copper indium gallium selenide (CIGS) is relatively small, and they can maintain good stability under light exposure.

Temperature effect

Monocrystalline silicon photovoltaic modules: The temperature coefficient of monocrystalline silicon modules is relatively small, generally ranging from -0.3% /℃ to -0.5% /℃. When the intensity of light increases, the temperature of the components will rise. However, due to its low temperature coefficient, the impact on the power generation efficiency is relatively small. However, in a high-temperature environment, its output power will still decrease to a certain extent.

Polycrystalline silicon photovoltaic modules: The temperature coefficient of polycrystalline silicon modules is similar to that of monocrystalline silicon modules. However, due to the characteristics of its internal structure, under the same light intensity, the temperature rise of polycrystalline silicon modules may be slightly higher than that of monocrystalline silicon modules. Therefore, in high-temperature environments, the decline in the power generation efficiency of polycrystalline silicon modules may be slightly greater.

Thin-film photovoltaic modules: The temperature coefficient of thin-film modules is generally larger than that of crystalline silicon modules. For instance, the temperature coefficient of amorphous silicon thin-film modules can reach approximately -0.8% /℃. This means that when the increase in light intensity leads to a rise in temperature, the power generation efficiency of thin-film modules decreases more significantly. However, in low-temperature environments, the performance of thin-film modules is relatively stable and may even improve to a certain extent.