【作者】 孙国辉；

【导师】 晏石林；

【作者基本信息】 武汉理工大学 ， 固体力学， 2010， 博士

【摘要】 随着化石能源的不断减少和能源需求的日益增加,可再生能源,特别是太阳能受到了广泛关注,作为太阳能利用重要组成部分的光伏产业迅速发展。而太阳电池组件在制造过程和服役过程中,由于材料的热膨胀系数不匹配,导致太阳电池组件内部产生残余应力,严重影响了太阳电池组件的使用寿命。本文围绕太阳电池组件制造过程电池片碎裂的机理和服役过程残余热应力的演变规律这两个关键问题,采用理论、数值模拟与实验相结合的方法开展研究工作,探索太阳电池片碎裂的机理,提出在太阳电池组件制造过程和服役过程中减少电池片碎裂的措施与方法。主要工作和结论如下：1、针对生产太阳电池片三道工序(铸锭、切片和烧结),开展太阳电池片制造过程的残余应力研究。采用有限元分析软件ANSYS对硅锭铸锭过程、切片过程和电极烧结过程进行数值模拟研究,分析了某些工艺参数对硅锭铸锭过程的残余应力的影响,模拟了硅片切割过程中应力的变化规律,并讨论了硅片层厚度和铝背场厚度对电池片弯曲度和残余应力的影响。2、针对太阳电池组件焊接过程中存在的问题,运用数值模拟技术分析太阳电池组件焊接工艺中的应力分布情况。讨论了不同的焊接区域对电池片的应力分布的影响,通过改变温度机制、焊接区域和焊条型号,优化出较为合理的焊接位置；分析了温度机制的影响,确定焊接过程合理的焊接温差；模拟不同型号焊条对电池片强度的影响,选出了较为合理的焊条。3、建立了太阳电池组件的温度场理论模型和应力场理论模型,分别计算太阳电池组件封装过程的应力场以及稳定服役过程结构的温度场和应力场；获得了太阳电池组件封装过程各层材料的应力分布情况,讨论了封装工艺对太阳电池片最大应力值及应力分布的影响；并与组件封装过程和服役过程热应力的数值结果进行比较,相互验证其模型的有效性,为太阳电池组件的热应力缓和设计奠定基础。4、采用平面应变模型分析了太阳电池组件在瞬态热载荷作用下组件热应力分布及演变过程,通过对温度场和应力场瞬态的耦合分析,得到太阳电池组件各层材料的温度和热应力分布及演变规律。找出了太阳电池组件的危险部位,确定了太阳电池组件承受的交变应力幅和应力峰值,为太阳电池组件的疲劳寿命评估奠定基础。通过分析比较工程设计中常用的寿命评估方法,提出适合太阳电池组件的疲劳寿命评估方法；采用小型冲压实验方法对太阳电池片的基本力学性能进行测试,获得太阳电池片的弹性模量和断裂强度等参数；采用经验公式获得材料的疲劳极限和疲劳性能参数,完成了太阳电池组件疲劳寿命的初步评估。本文通过理论研究与数值计算相结合,研究了太阳电池组件制造和服役过程残余应力的分布情况,讨论了组件封装过程对电池片产品本身结构的影响,分析了组件在热循环条件下的热应力分布及演变规律,揭示太阳电池片碎裂的机理；建立了太阳电池组件寿命评估方法,分析太阳电池组件疲劳寿命的影响因素,提出改善太阳电池组件疲劳强度和延长组件服役寿命的措施与方法,对太阳电池组件的设计和大规模生产利用具有重要指导意义。更多还原

【Abstract】 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.更多还原