From Silicon to Electricity SOLAR ENERGY PRESENTATION

From Silicon to Electricity 2© kontech GmbH 01Fundamentals Which market to enter? Which customers to target? 02Silizium Production 03Wafer Optical comparison / differences Technical advantages /disadvantages 4Production steps in the factory Production steps, broadly defined „Dirty Production“ Possible factory layouts Typical machinery / equipment 05Solar panel Panel manufacturing / Basic structure 06Feeding in electricity 07Inverters SOLAR ENERGY PRESENTATION

The Market Home owners  reasonably priced purchase and maintenance / simple installation Commercial investors – Major real estate  Longevity / outstanding performance / simple exchange – Solar farms of faulty units / safe monitoring (remote) Public entities  Longevity / outstanding performance 3© kontech GmbH The target group defines the wafer quality SOLAR ENERGY PRESENTATION

Silicon Production Silicon is a metalloid. The production of silicon (high-purity silicon) is very energy consuming. This makes it crucial to decide if this production step is outsourced or not. It is a process belonging to the area of „dirty“ production. The choice of silicon production depends on the desired result and the intended quality of the panel. ( multi crystalline / mono crystalline = thick layer cells) Further option „thin layer cells“ (String ribbon – to be carefully considered, since performance is significantly lower than with thick layer cells) Amorphous solar cells (silicon on a backing layer, like glas) Switching from one quality to another is costly and time-consuming. 4© kontech GmbH SOLAR ENERGY PRESENTATION

Silicon Production 5© kontech GmbH Silicon production, String ribbon (Source: Evergreen) Alternatively string ribbon can be produced by the so called octahedron process. Silicon ingot (multi crystalline) Silicon ingot (monocrystalline) SOLAR ENERGY PRESENTATION

Wafers - Comparison / Differences 6© kontech GmbH Multi crystalline Mono crystalline Multi crystalline: Squarish shape, „snow flake surface“, Mainly used for solar panels Mono crystalline : Rounded corners, since made from rounded ingots, uniform surface texture, used only for prime quality solar panels because of high production cost Standard sizes: 125mm x 125 mm 156mm x 156 mm SOLAR ENERGY PRESENTATION

Technical (Dis)Advantages 7© kontech GmbH Wafer typeAdvantageDisadvantage String ribbonNearly no wasteLow performance String ribbonComparatively cheap production Very special production process Multi crystallineCheaper than mono crystalline Good energy efficiency Multi crystallineIngot production is simpler than for mono crystalline wafer Less energy efficiency than a mono crystalline wafer AmorphousSuitable for diffuse lightLow energy efficiency SOLAR ENERGY PRESENTATION

Production steps in the factory Production steps, broadly defined „Dirty Production“ Possible factory layout I (Solar wafer production) Possible factory layout II (Panel production) Examples for manufacturing plants 8© kontech GmbH SOLAR ENERGY PRESENTATION

Production steps, broadly defined „Dirty Production“ Silicon block production Sawing the blocks into bricks / ingot size Sawing the ingot (multi / mono) to wafer thinness Cleaning the wafer (removal of slurries) Separating the wafers (critical process  possibly high percentage of breakage) 9© kontech GmbH Clean room production Etching off the saw damage ( so-called etching machine or edge isolation) Doping (phosphorous doping in the oven) Second etching (removal of phosphosilicate glass) Applicating the antireflection layer PECVD  Plamas process (costly – complex  possibly to be replaced by used material) Lithography (screen print) Welding of strings Production of panels SOLAR ENERGY PRESENTATION

„Dirty Production“ 10© kontech GmbH Wafer is sawn from the ingotSaw slurry removal by water (with additives) Milky water = Water with slurry SOLAR ENERGY PRESENTATION

Possible Factory Layout I (Solar wafer production) 11© kontech GmbH Production steps in clean manufacturing. From the clean, etched wafer to the classified wafer going into string production. SOLAR ENERGY PRESENTATION

Possible Factory Layout II (Panel production) 12© kontech GmbH Source: XINOLOGY From solar cell to solar panel - This is a fully automatic production line, but steps could be done manually without quality loss. SOLAR ENERGY PRESENTATION

Production Plant Example 13© kontech GmbH Saw damage etching incl. assembling Bildquelle RENA Chemical process. Warning: the chemicals involved for all processes are water- polluting substances! SOLAR ENERGY PRESENTATION

Production Plant Example 14© kontech GmbH Tube doping furnaceDoping furnaceFlow doping furnace SOLAR ENERGY PRESENTATION

Panel Manufacturing Solar panels have to fulfill a variety of requirements: -Safety for the user with regard to: Electrical safety Mechanical safety -Easy handling ( by handling technology / application technology / mounting aid) -Robustness can be achieved by: Protecting the panel from mechanical and thermic stress Protection against dampness. Durable electric connections 15© kontech GmbH SOLAR ENERGY PRESENTATION

Production Steps 16© kontech GmbH SOLAR ENERGY PRESENTATION

Solar panel construction 17© kontech GmbH SOLAR ENERGY PRESENTATION

Feeding in electricity Additional requirements: Inverter (one for a previously defined number of panels or pre-defined feed-in power). Inverters are produced at reasonable prices, one should consider a franchise or cooperation. Feed-in tariffs (taking into account that the house is not self-sufficient with regard to energy – electricity is taken from and fed back into the electricity grid) Remote access to electricity production (important for commercial energy farms)? To handle a multitude of minor and major feed-ins the area needs so-called „smart grids“. 18© kontech GmbH SOLAR ENERGY PRESENTATION

Inverters – Basic Facts There are different kinds of inverters, ranging from photovoltaic and UPS (Uninterruptible Power Supply) to lighting (e.g. ballasts for fluorescent lamps) Solar inverter: A solar inverter converts the direct current produced by the solar cell into alternating voltage. Only alternating voltage can be fed into the grid. There are different kinds of solar inverters. The choice depends on the technical requirements. From a technical viewpoint the difference lies in choosing an inverter with or without transformer. Those without transformers have a higher efficiency. 19© kontech GmbH SOLAR ENERGY PRESENTATION

Inverter Production Required production units: Circuit board manufacturing (Lamination) Circuit board manufacturing (Manual or automatic assembly, welding by reflow furnace. Manual welding is possible, but not recommended) and testing the finished circuit boards Case production Final mounting – (circuit boards into casing) Calibration / software installation on the end device (may be done while testing the circuit boards) Functional check 20© kontech GmbH SOLAR ENERGY PRESENTATION

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