The Study Of Crystal Silicon Solar Module Power Loss

In this paper, the main study is improving the power of the module,following several aspects are researched:1. Research on module powerIn this section, the module power loss after encapsulation was studied.The following conclusions were achieved:(1) The effective method to improve optical gain of the module is to usea high light transmittance glass and the strong blue spectral response cellwhile matching the best blue light transmittance EVA and high reflectancebacksheet.(2) The power loss of the weld strip can be up to80%of electricalpower loss. Therefore, an effective way to reduce the electrical power loss isto reduce the resistance of the weld strip.(3) The contact resistance between weld strip and bus bar causes a verylittle power loss, usually below1%, can be ignored.(4) In the same cell conversion efficiency of the case, the lower seriesresistance can reduce the current of the maximum power point of the module,and to reduce power loss caused by the series resistance, to improve theoutput power of the module.2. Research on the convert efficiency of solar cell.In this section, the effect of series resistance on the cell convertefficiency was studied emphatically. The following conclusions wereachieved:(1) The relationship between cell’s series resistance and cell’s convertefficiency is negtive. The series resistance is lower, the convert efficiency is higher.(2) The series resistance has positive relationship with temperature, andits value is closely related to the points (I,V) values.(3) In the series resistance components, the body resistance, surfaceresistance, bus bar resistance and finger resistance all can be accuratelycalculated, but the contact resistance can’t accurately calculated byTransmission Line Model (TLM) method which has greatly deviation.3. Research on measurement method for contact resistance of the solar cell.Three contact resistance expressions were deduced by establishingvoltage and current equations of the metal-semiconductor interface in thedifferent current mode, and three new methods on the basis of the traditionalTLM were approved: Different Space TLM(DSTLM) method,Same SpaceTLM(SSTLML)method and improved End Resistance (ER)method. Thefollowing conclusions have been achieved:(1)One contact resistance can be easily calculated from the other twocontact resistance, so it is unnecessary to calculate specific contact resistivityand sheet resistance.(2) DSTLM can accurately measure the contact resistance,but it requiresmaking special test pattern and it is not convenient for solar cells.(3) SSTLM can directly measure the contact resistance when the sheetresistance was measured accurately in diffusion process. SSTLM does notneed to make special test pattern, so it is convenient for solar cells.(4)The improved ER method breaks the restriction of only three parallelelectrodes of traditional ER method and expands the number of electrodes.(5) The current of tester has an influence on the measured value ofcontact resistance because the contact resistance of cell is rectified resistance.