聚光能流参数对背接触电池阵列输出特性的影响

Influence of Concentrated Illumination Parameters on the Output Characteristics of Back Contact Solar Cell Array

主要研究了聚光能流特性对槽式聚光热电联供系统电输出性能的影响。通过CCD相机测量不同距离和不同镜面开口宽度焦平面上的能流分布图获取能流值分布矩阵,提取能流参数,包括相对平均能流值、不均匀度、峰值偏离度和能流利用率。通过引入聚光条件下电池内部复合机制和寄生电阻,建立了聚光电池阵列的双指数等效电路模型,模拟结果与实验结果吻合得较好。结果表明,短路电流和相对最大功率随相对平均能流值的增加而增加,两者的增大率分别因复合机制的增强和寄生电阻欧姆损失的增大而减小;开路电压随不均匀度和峰值偏离度的增大而减小;相对平均能流值因寄生电阻欧姆损失对填充因子影响最大;电池的效率由能流利用率和相对平均能流值决定。以6片串联2cm×2cm的背接触电池阵列为例,当镜面开口宽度为157cm、距焦平面2cm时,平面上的能流分布最适合电池阵列的性能输出。

This work investigates the influence of the concentrated illumination characteristics on the electrical output performance of photovoltaic/thermal system under trough concentrated sunlight. By measuring the illumination distribution at the focal plane for different distances and different opening widths of mirror with the CCD camera, the illumination value distribution matrix is acquired, from which illumination parameters such as average illumination value, nonuniformity, peak deviation degree and illumination utilization ratio are extracted. The double exponential equivalent circuit model of the concentrator solar cell array is acquired by introducing recombination mechanism and parasitic resistance of the cell under the concentrated sunlight, and the simulation results agree well with the experimental records. The results show that the short circuit current and the relative maximum power increase with the increase of the relative average illumination value, and the degree of increase becomes smaller due to the intensifying of the recombination mechanisms and the increase of the ohmic losses for parasitic resistance, respectively. The open circuit voltage decreases with the increase of the non-uniform illumination degree and the peak deviation degree. The relative average illumination value has a greatest influence on the fill factor because of the ohmic losses for parasitic resistance. The conversion efficiency of solar cell depends on the illumination utilizationratio and the relative average illumination value. Taking series array of 6 pieces of 2 cmX 2 cm back contact ceils as an example, it can be concluded that, when the opening width of mirror is 157 cm and the distance from focal plane is 2 cm, the illumination distribution is the most suitable for the performance output of the back contact solar cell array.