晶硅电池在低倍聚光条件下短路电流变化规律分析

ANALYSIS OF SHORT CIRCUIT CURRENT OF SILICON CELLS UNDER LOW CONCENTRATION

在对常规晶硅电池的性能测量过程中发现,在常温非聚光情况下,晶硅电池短路电流Isc与温度保持线性关系;但在高温低倍聚光情况下,短路电流Isc出现偏离线性的现象。使用双二极管的晶硅电池等效模型进行分析,简化短路电流表达式。在此基础上使用公式对Isc出现的偏离线性现象进行分析,指出并联电阻Rsh与串联电阻Rs的量级变化差别,引起Isc出现偏离线性,并据此定义了一个短路电流偏离线性系数αIsc。分析了短路电流偏离线性系数αIsc对Isc偏离线性的影响,在高温低倍聚光情况下,αIsc<1,晶硅电池的Isc出现明显下降。因此,在低倍聚光情况下,具有大并联电阻Rsh的晶硅电池,即αIsc≈1,能保证输出电流的稳定性。

In measuring the performance of silicon cells, it is found that the crystalline silicon cells＇ short circuit current Isc and temperature maintain a linear relationship without concentration at normal temperature, but short circuit current and temperature don＇ t keep a linear relationship under low concentration at high temperature. The two diode equivalent model of the crystalline silicon cells was used to analyze the expression of short circuit current, and the phenomenon deviating linearity of I^c, which was caused by the difference of magnitude changes of the shunt resistance Rsh and the series resistance Rs. Hereby, a coefficient aIac was defined, which was used to indicate whether short circuit current Iac and temperature maintain a linear relationship. The connection between this coefficient Iac and the performance of short circuit current at different temperatures and concentrations was analyzed.