Research And Performance Optimization Of PERC Battery With Reshaping Laser Selective Emitter

Photovoltaic power generation is a green,safe and pollution-free way of supplying energy.Solar cell is the core component of the photovoltaic module,especially the passivated emitter and rear cell(PERC)solar cells,which have been favored for its ultra-high conversion efficiency.Improving the solar cell conversion efficiency has long received great attentions in the fields of industrial research and application.Among various efficiency improvement technologies,selective emitter structure is a new technology featuring with broad industrial application potentials.by formulating the densely doped area under the metal electrode,it can reduce the contact resistance.The area between the metal electrodes is slightly doped,which reduces the recombination rate of current carriers and increases the lifespan of the minority carriers.The combination of these two kinds can further improve the efficiency of monocrystalline solar cell.By combining the solar cell production process,this paper adopts the shape laser to produce the selective emitter of PERC solar cell in order to analyze the mechanism of solar cell performance improvement.Through optimizing the metal electrode that matches the selective emitter,the solar cell performance is optimized.The following aspects are discussed in the paper.(1)The structural characteristics of selective emitters are analyzed by comparing and analyzing the current production technology.Combined with the research and development requirements for battery production,this paper emphasizes the preparation of selective emitter structure by direct-doped phosphorous-silica glass(PSG)into shape laser,as well as discusses and analyzes the principle of selective emitter to improve solar cell contact resistance,short-circuit current,open circuit voltage and conversion efficiency.(2)According to the theoretical formula of laser spot overlap rate,the laser energy density is considered to study the role of the laser spot on the silicon wafer and the change of energy density on the laser path.The effects of laser energy density on silicon morphology,sheet resistance,doping concentration and P-n knot depth are analyzed.(3)Combined with the solar cell production,the PERC solar cells are produced with the shape laser technique.Under the premise of the optimal laser doping,the efficiency from this PERC solar cell production line can reach 21.69%.In order to improve the photoelectric efficiency of the solar cell while ensuring the battery quality,the electroluminescence(EL)test is used to analyze the inefficiency cause of the PERC solar cell.(4)The series resistance model and power loss of the front side for the selective emitter PERC solar cells are analyzed.The paper carries out the numerical stimulation on the power loss of the front side and conducts analysis by combining the measured solar cell electrical performance data.according to the numerical simulation results,the electrode design matched with the optimized shape laser doping process is designed.Finally,the optimized electrode design is applied to the battery process production so that the photoelectric conversion efficiency is further increased to 21.85%.(4)Combining the PERC solar cell process,this paper systematically optimizes the shaped laser doping process to prepare the selective emitter,realizing the efficiency improvement of PERC solar cells.Meanwhile,it provides the theory and application foundation for applying the shaped laser doping in producing crystalline silicon cell.The research results show that the preparation of selective emitters with shaped laser has a great application prospect in PV market.