A 280 MW – 62 million pieces – Poly crystalline PV cell manufacturing unit at Baddi, Himachal Pradesh.
Started commercial production in March 2010
Manufactures of the highest efficiency PID resistive Cells in India – at par with the global leaders.
Centrotherm Photovoltaics AG
S C New Energy Technology Corporation
The unique feature of our Cell manufacturing process is the use of Selective Emitter technology. Very few in the world use this technology.
This technology enables to increase the efficiency of the Cells by up to 0.4%
Selective Emitter Technology
The basic structure of silicon solar cells is based on two positive and negative doped areas. The charge carriers generated by the photo effect are separated by this p-n junction and conducted externally via metal contacts on both sides. The emitter doping is always a compromise in standard solar cells with homogenous emitters. A high n-doping is required in the emitter layer to minimize the resistivity between semiconductor and metal contacts. However, recombination losses increase with rising phosphorous concentration which has an adverse impact on power generation.
Thanks to selective emitter technology, the phosphorous concentration in the emitter can be controlled, so that only the area of the front side metal grid has a high phosphorous concentration and therefore a low emitter resistivity. The rest of the surface is lower phosphorous doped so that a large part of the cell can be used for electricity generation. This combines an improved solar cell performance with very good ohmic contact.
In comparison to the standard process, an additional production step is required for the manufacture of selective emitter solar cells. After POCl3 diffusion, some of the phosphor in the phosphosilicate glass is diffused precisely and without any defects into the Cell surface.
For this purpose a laser tool which can increase cell efficiency by up to 0.4% is used.
Chemical Edge Isolation (Back Side Etch )
The P-N junction is isolated by optimized back side etching process that will provide the extra area for current generation than the laser edge isolation. Also gives High Shunt Resistance and lower Reverse current . That make sure solar cells perform exceptionally at customer sites.
Manufacturing Process using Selective Emitter & Chemical Edge Isolation (Back Side Etch)
We have integrated this selective emitter technology & Chemical Edge Isolation (Back Side Etch) into our production line and improved the average efficiency of our cells to 18%