Research, Preparation And Characterization Of Self-cleaning Film For Photovoltaic Modules

The high-efficiency self-cleaning film assembly can further improve the power generation of the photovoltaic module and increase the power generation income Meanwhile,it can reduce the pressure of operations and cleaning times.So there is a widely application prospect.In this paper,SiO2/TiO2 coating solution was prepared by sol-gel method and coated on the surface of photovoltaic glass.The effect of the self-cleaning film on the light transmittance,super hydrophilic property,dust adhesion resistance,decomposition of organic matter and weather resistance of the glass was studied by XRD,SEM and UV.The TiO2 sol was prepared by using tetrabutyl titanate as the precursor,and the SiO2 sol was prepared by modified StOber method with ethyl silicate as the raw material.The self-cleaning coating solution was prepared by mixing titanium sol and silica sol with some additives.The small samples were prepared by lifting and dipping method in the laboratory test,and large plate photovoltaic self-cleaning film glass was prepared by roller coating machine and tempered furnace.The pencil hardness and adhesion level of the self-cleaning film is 4H and 0,respectively.The glass transmittance was increased by 2.2%with the self-cleaning film,which meet the requirements of the photovoltaic module anti-reflection film layer.The presence of TiO2 nanoparticles in the self-cleaning film has some effect on the transmittance of the film.When the ratio of TiO2 solution to diluted SiO2 solution is less than 1:1.5,the precipitation of TiO2 nanoparticles begins to appear.When the ratio is 1:2,the comprehensive test is better.The self-cleaning film possesses the dual effect of photocatalytic to superhydrophilicity and roughness superhydrophilicity.The minimum static contact angle detected under sunlight is 4.780,and the minimum contact angle after 10 days of shading is 6.30°.The super hydrophilic effect enables the self-cleaning film layer to wash the dust on the surface of PV modules completely and quickly with the help of rain or little water.The surface of self-cleaning film layer forms 20～30nm particle accumulation,which has a certain degree of micro roughness.The dust can slide down freely under the action of gravity and the wind to avoid dust adhesion and accumulation.The photocatalytic degradation of organic matter can degrade organic particles into smaller ones to compete decomposition,which can effectively prevent the organic and chemical hardening of dust.The light transmittance of self-cleaned film glass decreased to less than 1%in the laboratory after accelerated aging under high temperature and high pressure,wet heat test and wet freezing test.However,the light transmittance of self-cleaned film glass increased slightly after ultraviolet test.After all kinds of weather resistance tests,the film still has super hydrophilic effect.In the control experiment of 4 months at the photovoltaic power station,the self-cleaning photovoltaic module with the self-cleaning film can increase the power generation by 4%with less dust on the surface of the glass.The result achieved the desired effect.