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The
Making of a Solar Cell
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As far back as 1877, Werner Von Siemens recognized the importance of photovoltaic technology: "...this is a completely physical phenomenon which is of enormous scientific significance, ...since we have …..witnessed here for the first time the direct conversion of the energy of light into electrical energy."
Today photovoltaic systems offer an attractive solution for increasing numbers of applications that demand an economic and reliable power supply-even under extreme environmental conditions.
Siemens manufactures an extensive range of high quality solar modules using innovative technology. Our continuously refined and field-proven products provide the optimum answer to practically every energy requirement-from just a few watts up to megawatts. Choosing Siemens solar modules means that you have the ultimate in quality, both now and for the future.
 The high quality of Siemens Solar products is the result of ongoing refinement and optimization of the production process. Siemens solar cells are based on single-crystalline silicon technology that offers better efficiency than
multicrystalline, amorphous silicon or other thin film technologies. Silicon is environmentally friendly, and there is almost unlimited availability in the form of silica sand. Purified poly-crystalline silicon is melted and grown into round single-crystalline ingots. The ingots are used in round shapes or are trimmed to produce an almost square cross-section. This shape makes optimum use of the module surface area.
 The blocks are cut into wafers using a very low-loss sawing process. To improve light absorption, the proprietary TOPS tm process is used. The surface of each wafer is given a pyramid shape by means of a special textural etching process. The subsequent phosphorus doping of the already boron doped wafers provides the electrical means of exploiting the photovoltaic effect. An anti-reflective oxide coating is applied to each wafer to enhance energy production. Silver paste is applied to the front and back of the solar cell forming electrical circuit contacts using inexpensive screen-printing technology. The subsequent firing process guarantees maximum electrical conductivity.
Once tested, the solar cells are electrically connected to form strings and are protected by a proven modular design. The cell strings are embedded in EVA between specially hardened, highly transparent from glass and a multi-layer back sheet to protect them against moisture, ensure UV stability and provides electrical insulation. The components are laminated at high temperature to form a securely protected encapsulation.
At the end of the production process, the module is fitted with a torsion-resistant frame made of anodized aluminum with extremely high mechanical stability.
Bypass diodes in the junction boxes protect the cells from excess local heating should partial shading of the module occur.
Exclusive to Siemens Solar is the PowerMax R junction box which provides for easy module connection using cable, conduit or wire. This junction box is available on many of our modules.
The optical, mechanical and electrical function of very module is tested in detail before it leaves our factory. Each module is labeled with a bar code and a serial number.
The ingot is sawn into wafers that are specially treated and further processed into solar cells.
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