The Research Of Fast Potential Induced Degradation Technology For Crystalline Silicon Solar Cells

Solar energy is an important part of modern energy system.And it is one of the key links in solar energy utilization technology to ensure the long-term stability of photovoltaic(PV)system.Potential induced degradation(PID)is one of the most common phenomena that affect the stability and reliability of crystalline silicon solar cells during their actual operation.PID is a phenomenon in which a high potential in a PV system triggers a significant drop in module output power.The attenuation caused by the PID phenomenon can greatly reduce the output power of PV modules and cause large economic losses,which required optimizing the structure and materials of PV modules to obtain a certain resistance to PID.It is important for PV manufacturers to pre-test the PID resistance of their productions to ensure the quality of their modules.Traditional PID test techniques are mainly tested for PV modules.The test method for PID of modules needs to be performed in a special hygrothermal laboratory,which usually takes 96 hours.And most manufacturers also adopt more stringent standards for the test to improve products quality.Although the traditional testing method can comprehensively demonstrate the anti-PID performance of PV modules,PID testing of modules is too tedious for cell manufacturers.Due to the introduction and influence of packaging materials such as glass,adhesives,and sheets,the anti-PID characteristics of the cells cannot be accurately obtained,while the lengthy testing process also brined product quality risks during the test.The traditional testing methods appear to be less economical and the feedback of results was not timely.Therefore,the study of fast potential induced degradation technology at the cell side has considerable practical and economic value for cell manufacturers.In this paper,a fast PID treatment and testing technique for crystalline silicon solar cell was investgated and developed based on the PID principle.A fast PID setup for crystalline silicon solar cells was built,a corresponding test procedure was developed,and a real-time monitoring method for the cell PID effect during the testing of crystalline silicon solar cells was proposed.The setup was also used to conduct experimental studies on four key factors affecting the fast PID treatment of monocrystalline silicon passivated emitter and rear contact(PERC)solar cells--temperature,voltage,treatment time,and illumination.Firstly,the working principle and technology development of solar cells were introduced,the manufacturing process and material composition of crystalline silicon photovoltaic modules were described,the causes and mechanisms of the PID effect were detailed,the test methods commonly used to detect the anti-PID performance of photovoltaic modules were introduced,and the importance of developing rapid PID detection means in cells was illustrated.Secondly,this paper further investigated cell PID theory in depth,established a method to achieve fast PID detection at the cell according to the cell PID principle,built a cell fast PID test setup independently,and developed a reliable treating process.The PID testing of sample cells was carried out using the built test platform,and the surface morphology,defects and elements at the defects of the cells before and after treatment were analyzed by a series of characterization means.It was shown that the designed PID platform can effectively simulate the PID treatment at the cell,thus realizing the fast PID detection at the cell.Thirdly,based on the fast test setup of crystalline silicon solar cell built by ourselves,this paper further studied and developed the real-time monitoring technology of PID effect during the treatment of P-type crystalline silicon solar cell.By analyzing the equivalent circuit,current-voltage characteristics and power-voltage characteristics of crystalline silicon solar cells,the relationship between cell decay rate and shunt resistance during the treatment was obtained,and thus a method for real-time monitoring of solar cell decay rate was established.The method was further validated by experiments;meanwhile,the calculation method was further optimized in the calculation process,and the important parameter of cell PID area to effective area ratio was calculated by using digital image processing technology combined with EL characterization means.This parameter was introduced into the calculation equation of cell decay rate implementation monitoring,thus obtaining more accurate test results.Finally,in this paper,based on the existing experimental platform,four important factors in PID,including temperature,voltage,processing time,and light,were investigated with P-type PERC solar cells.The influence of each parameter on the cell PID process was studied separately,and a locally better combination of each test condition was obtained within a reasonable range of conditions,and the technical processing conditions for fast PID at the cell were given in combination with this parameter combination.In this paper,further insight into the PID of crystalline silicon solar cells was gained and the feasibility of the fast test setup as well as the real-time monitoring technology for crystalline silicon solar cells was verified.At the same time,the research results provided a certain basis for the application and promotion of the cell-side fast PID test platform,and surporting the high-quality development of PV.