From Short-term Hotspot Measurements to Long-term Module Reliability

In order to reach high module reliability, all solar cells with a potentially critical hotspot have to be neglected during cell sorting. This is essential to avoid delamination in case of partial shading of the module. Due to throughput considerations, the finished solar cell has to be classified within some milliseconds. In consequence the short-term hotspot heating measurement has to be correlated to absolute hotspot temperatures for various module conditions in the field. Previously it has already been shown that a definite mapping of these quantities is not possible, requiring further investigations in order to quantify the risk for possible module damage.In this contribution, the probability distribution for absolute hotspot temperatures in the module will be calculated from short-term hotspot measurement data, considering temperature-dependent reverse biases. Together with experimental data for module delamination temperatures, the probability of module failure can be calculated in a direct way.