Residual Stress Study On Manufacturing And Service Process Of The Solar Cell Module

With the decrease of fossil energy and the increase of energy need, reproducible energy, especially solar energy has drawn extensive attention. Potovoltaics technology is developing rapidly as an important way of using solar energy. During the manufacturing and service processing of solar cell module, residual stress produced in internal of solar cell module because of thermal expansion coefficient of materials mismatch, which influenced the life of solar cell module seriously.Focused on the two key issues, the fragmentation mechanics of cell in the manufacturing process and the evolution of residual thermal stress in service process of solar cell module, the paper investigated the mechanics of cell fragmentation and proposed some measures to reduce the cell fragmentation through three aspects contained theory, numerical simulation and experiment. The main works and conclusions are summary as follow:1. The residual stress produced in the manufacturing process of solar cell module was investigated aimed at the three processes (ingot casting, slicing and sintering) for solar cell production. Numerical simulation was carried on the ingot casting of silicon, slicing and the electrodes sintering process by finite element analysis software ANSYS, analyzing the effect of some crafts parameters on the residual stress, simulating the evolution of stress in the silicon slicing process, discussing the effect of silicon thickness and aluminum-alloyed back surface field thickness on cell flexural value and residual stress.2. Stress distribution in the welding process of solar cell module was analyzed by using numerical simulation aimed to the problem in the welding process of solar cell module. The effect of welding location on stress distribution of solar cell was discussed. By changing the temperature mechanism, welding location and welding rod type, suitable welding location was obtained; the effect of temperature mechanism was analyzed and suitable welding temperature was choosed; the effect of different types of welding rods on the intensity of cell was simulated and suitable welding rod was obtained.3. The theory model of temperature field and stress field in solar cell module was built. The stress field in packaging process of solar cell module and temperature field in service were calculated respectively. The stress distribution of each layer material in packaging process of solar cell module was obtained. The effect of packaging technique on max stress value and stress distribution of solar cell was discussed. The validity of model was confirmed by comparing the thermal stress of theory model with results of numerical simulation, which lay the foundation for thermal stress relaxation design of solar cell module.4. The thermal stress distribution and evolution of solar cell module under the transient thermal loads were analyzed by plane strain model. The temperature and thermal stress distribution was obtained by the transient temperature field and stress field coupling analysis. The dangerous area of solar cell module was identified, and alternating stress amplitude and the stress peak on solar cell module was obtained, which lay foundation for the fatigue life evaluation of solar cell module. The suitable fatigue life evaluation method was proposed by comparing life evaluation method commonly used in engineering design. The basic mechanics performance of solar cell was tested by small punch method, and elastic modulus and ultimate strength was obtained. The fatigue limit and fatigue performance parameters of material were obtained by empirical formula. The fatigue life elementary evaluation of solar cell module was finished.In summary, in this work we investigated the residual stress distribution of solar cell module in manufacturing and service process, discussed the effect of packaging process on the structure of solar cell, analyzed the thermal stress distribution and evolution of solar cell module on the thermal cycle, revealed the fragmentation mechanism of solar cells, built the life evaluation method of solar cell module, analyzed the factors on fatigue life, gave some measures and method to improve the fatigue intensity and service life of solar cell module. The work has important guiding significance to the design and large scale production of solar cell module.