基于光谱选择的太阳电池被动冷却材料研究进展

太阳电池的光电转换效率随着组件温度升高而降低,适当冷却可以改善电池效率,延长使用寿命,因此人们对运行中太阳电池的冷却问题越来越关注。相比主动冷却,太阳电池的被动冷却具有自我维持和无额外能耗等优势,近年来被广泛研究。其中基于光谱选择的被动冷却主要包括两个方面:一是选择性地屏蔽太阳辐射(0.3~2.5 μm)中的亚带隙光,减小吸收热,但保持光电响应波段光的高透射率;二是提高光伏表面中红外波段(4~25 μm)的发射率,提升寄生热的辐射散热能力。本文从光谱选择的角度出发,对促进太阳电池降温的太阳光谱选择、辐射制冷及全光谱选择的材料和结构进行了归纳和总结。通过刻蚀、溅射、辊涂等方法在玻璃表面制备的光谱选择材料可以屏蔽太阳光谱中不激发光电效应的波段,增强中红外辐射制冷能力,从而有效降低光伏温度和提高光电转换效率。此外,文章还对被动式制冷材料的产业化潜力进行了展望,为相关的开发提供参考。

Research Progress on Spectral-Selective Materials for Passive Cooling of Solar Photovoltaics

The solar photovoltaic (PV) technology undergoes a linear decrease in photoelectric conversion efficiency when the PV operating temperature increases. But proper cooling can improve PV efficiency and prolong its service life. Thus, with the annual increase of PV installation, people pay more attention to the cooling of operating PV. Compared with active cooling of PV, recently, passive cooling is widely studied due to its self-sustained nature and energy-saving. Passive cooling based on spectral-selective includes two aspects. One is to selectively shields the sub-bandgap absorption in the solar radiation region (0.3~2.5 μm), reduce the generation of absorption heat, and maintain the high transmittance of photoelectric response light. The other is to improve the emissivity of the mid-infrared region (MIR) (4~25 μm) of the PV surface, and enhance the radiative cooling ability of the parasitic heat. In the view of spectral-selective, the materials and structures of solar spectral-selective, radiative cooling and all-optical spectral-selective to promote the cooling of solar photovoltaics were summarized. The spectral-selective materials on glass were fabricated by etching, sputtering and painting to eliminate sub-bandgap absorption heat and enhance radiative cooling capacity. They can effectively reduce the PV temperature and improve the photoelectric conversion efficiency. In addition, the industrialization potential of passive cooling materials was prospected, which provided reference for related exploration.