The Detection Method For Solar Cell Based On Noise

Since its advantages in environmental protection and low running costs, the photovoltaic systems are widespread recognized and are being applied popularity in energy supply area, recently. Solar cells are the core of the photovoltaic systems. It is of vital importance to guarantee the quality in production and the reliability in utilization process, so it urgently needs to detect the quality and reliability of the solar cells.Up till now to assess the solar cells quality are analysis the series and parallel resistant from the measurement of the solar cells I-V characteristic curve. There are two defects in this method. On the one hand, the parameters from this method are insensitive to the influence elements on quality and reliability such as the materials defects; on the other hand for the different testers use diversity calculation methods there are more errors and differences on the solar cells evaluation results. Some scientists study the solar cells breakdown features by the electroluminescent method. This method has some weaknesses, such as the complex measurement procedure, the results are not as accurate, as well as the solar cells breakdown voltage is not enough precise. Specific to the above defects, a new solar cells detection method are present.Noise as a diagnostic tool for electronic component quality evaluation and reliability has been widely accepted. It can get the more detailed information about the device internal defects by measurement the excess noise which is caused by the potential defects.Above all, a noise solar cell detection method is given in this article. It also gives out the detecting processes to the different noise. Following will show the main work in this article:a) We make use of the maximize density of the voltage noise power spectrum and the quality factor based on the noise as the noise quality evolution parameter, to assess the quality of solar cell. To compare the noise parameters with the conventional electronic parameters from the measurement and analysis of the noise, it come out that noise is a conventional and effective tool to evaluate the quality of solar cells.b) Reliability evolution parameters are proposed by analyzing the characteristic under the forward biased and the reversed biased noise, respectively. By comparing the noise measurement results on the forward and reverse biased with the damage under the thermal stress test, we proved the noise reliability parameters can assess the solar cells utilize reliability.c) That the noise can judge the breakdown stages of the solar cells is presented and proven by study the breakdown stages when the solar cells are reversed.d) By studying the characteristics of local avalanche breakdown when the solar cells are reversed by higher voltage, measuring the solar cell microplasma noise, comprehensive analyzing the results of frequency and time domain, the duty ratio of the pulse current caused under the microplasma noise state has been got. Combining the duty ratio and the wide of the depletion layer, the volume of microplasma noise local region has been confirmed.