What are the effects of outdoor temperature on the output performance of solar panels?
Issuing time:2020-01-13 16:55
About the knowledge of solar panels, the editor of portable electronics came to talk about it again today. Do you know what the photoelectric conversion efficiency of solar panels is expressed in? What does it mean? Have you understood it?
Photoelectric conversion efficiency of solar panels
的 The photoelectric conversion efficiency of a solar panel is represented by η, which means the ratio of the incident output power of the solar panel to the power of the incident light irradiated onto the battery.
的 The photoelectric conversion efficiency of solar panels is mainly related to its structure, P-N junction characteristics, material properties, battery operating temperature, radiation damage to radioactive particles and environmental changes. The forbidden band width of the material directly affects the photo-generated current, that is, the magnitude of the short-circuit current. Due to the different energy levels of photons in solar radiation, only those photons with energy greater than the forbidden band width can generate electron-hole pairs in the semiconductor, thereby forming a photo-generated current. Therefore, the width of the material's forbidden band is small, the number of photons smaller than it, and the obtained short-circuit current is larger. Conversely, the wider the forbidden band, the smaller the number of photons larger than it, and the shorter the short-circuit current. However, the band gap width is too small, because the remaining energy of photons with energy greater than the band gap will be converted into thermal energy, which will reduce the utilization of photon energy. Furthermore, the width of the forbidden band directly affects the magnitude of the open circuit voltage. The magnitude of the open circuit voltage is inversely proportional to the magnitude of the reverse saturation current of the P-N junction. The larger the forbidden band width, the smaller the reverse saturation current and the higher the open-circuit voltage. Calculations show that the theoretical conversion efficiency of single crystal silicon solar cells can reach 33% when tested under the condition of atmospheric quality of AM1.5. The conversion efficiency of conventional commercial single crystal silicon solar panels is generally 18% ~ 21 %; The conversion efficiency of the polycrystalline silicon solar panel is 15% to 18%.
Effect of temperature on the output performance of solar panels
Temperature changes significantly change the output performance of solar cells. It can be known from semiconductor physics theory that the carrier's diffusion coefficient increases with increasing temperature, so the photo-generated current IL also increases with increasing temperature. However, 1o increases exponentially with increasing temperature, so V. It drops sharply with increasing temperature. When the temperature increases, the shape of the 1V curve changes, and the fill factor decreases, so the photoelectric conversion efficiency decreases with increasing temperature.
Article classification: 解决方案