| Improving the photoelectric conversion efficiency of photovoltaic cells,diversifying the development of new products for photovoltaic power generation,and reducing the production cost of products have become the theme of new technology development.The efficiency of crystalline silicon solar cells is increasing at a rate of 1%per year,and the module price have dropped to about 1.85 yuan per watt in 2019.The main reason for the increase in efficiency and cost reduction is the technological development from raw and auxiliary materials,silicon wafers,processes,and high-efficiency structures.The application fields of new products are gradually expanding from ground power station,roof distribution development to islands,transportation,automobiles and so on.Among them,the thinner wafer w and related cell production technologies have rarely reported.Moreover,the diversified BIPV components needs to be urgent due to the existing BIPV components are mostly planar components.In this paper,the in-depth research on mechanism of cells with using thinner wafer and its mechanical stress are carried out.The key technologies of a BIPV module with thinner c-Si solar cells have been completed.The main works are as follows:The mechanism of solar cells,the status and trends of solar energy development,the basic manufacturing process of solar cells are given in this thesis.The test principle including the mechanical properties test,the IV curve,the withstand voltage test,the insulation test,the mechanical load test,the test significance and the test method of the hail test,and test standards for qualified PV modules have been introduced.The paper gives the performance variation with the wafer thickness from 60μm to 180μm by PC1D simulation software.The Voc increases with decreases of the thickness of the silicon wafer,while the current decreasesand fill factor increases.The cell efficiency increases on 180um and then decreases as the thickness decreases to 60μm.The efficiency is highest at 130 microns to 140 microns.130 micron wafers were prepared by diamond-saw cutting method.The 130μm cells were prepared on the production line.The efficiencies of 130μm cell and 180μm were basically the same.The Voc of the 130 micron cell is 1.7 mV which is higher than that of the180μm cells.The Jsc of the 130 micron cell was is 0.2 mA/cm~2which is lower than that of the 180μm cells.The fill factor of the 130 micron cell is slightly lower than that of the 180micron cell.The efficiency of 130μm cells is 19.13%.The mechanical properties of the three-point method and the four-point method were tested.The maximum bending displacement,maximum load,and breaking load of the four-point bending test were 1.25times,1.67 times,and 1.58 times,respectively,than that of the three-point bending test.Meanwhile,130 Micron cells have greater bending displacement than 180 cells.The maximum load of a 130 micron battery is 6.13N,the maximum load of a 180μm cell is9.98N,respectively.The bending strength of a 130 microncell is 15.87mm,which is 2 times than the bending strength of 7.87mm in a 180 micron cell.It can be seen that the 130μm cell has better flexibility than the 180μm cell,indicating it is suitable for preparing flexibility BIPV component.Based on 130 micron cell,a curved BIPV module was fabricated with an arc height of 27mm.T.The production process such as the lamination process parameters is optimized the problems of bubble generation and opening of the component are solved.The center and the surface of the curved glass are detected separately.The impact resistance of the three points of the point and the lowest point of the surface is selected,and the lowest thickness curved glass conforming to the national safety standard is selected.The IV data is tested and the actual power generation is detected by the 220V grid connection through the micro inverter.The power generation efficiency is not lower than that of the conventional BIPV component.These results show curved BIPV module meets requirements in building field. |
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