Here are two videos explaining how solar PV panels are made. One video is produced by Trina Solar and one by Discovery (How It's Made Series).
The main raw material is silicon and, according to some independent engineers, the price of solar panels is still too high considering what they're made of.
Wikipedia fact: Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure free element in nature.
Since I'm also interested in camera work and video editing, I'm impressed with the quality of the video made by Trina. This shows that they care.
In case you'r connection doesn't allow you to watch video, I made a transcript of the first video:
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Founded in 1997, Trina Solar is a pioneering manufacturer of high quality photovoltaic modules.
Listen on the New York Stock Exchange since 2006, Trina Solar is currently one of the few PV manufacturers to have developed an entirely vertically integrated business model.
From the production of ingots, wafers and cells to the assembly of modules.
This integrated value chain allows us to continuously improve our production process, provide high quality products to our customers and maintain one of the lowest cost structures in the industry.
Trina Solar produces and markets a wide variety of photovoltaic modules, employing both monocrystalline and multicrystalline technologies with power outputs ranging from 165 W to 240 Watt peak.
Over the past 4 years Trina Solar managed to dramatically increase its production capacity from 75 MW in 2006 to 600 MW at the end of 2009.
We purchase silicon and other raw materials from a variety of international suppliers.
The silicon is tested and sorted according to its technical properties.
The quality of the raw material is one of the most important factors, determining module performance.
Ingots
Before inserting the silicon inside the crucible, the crucible must be coated with silicon nitride powder. The crucible is then baked in order to dry the coating layer.
To produce multicrystalline ingots, the silicon is first loaded into large crucibles which have a capacity of 250 to 450 kg. The crucibles are then loaded into furnaces. The silicon will then be melted gradually inside the furnace.
The molten silicon is changed into block from through this casting process.
Crystallization starts by gradually cooling the crucibles in order to create multicrystalline ingot blocks.
Wafers
To produce multicrystalline wafers, multicrystalline ingots are first cut into a predetermined size. The ingots are then individually tested before cutting in order to confirm the quality of the ingot.
The multicrystalline ingots are cropped to remove impurities.
To insure maximum quality, the surface of the ingot is then polished and the edges are grinded. Finally, the usable parts of the ingots are sliced into wafers by wire saws, using high precision cutting techniques which utilize steel wire and silicon carbon powder.
After this process, the wafers go through a cleaning procedure to remove debris from previous processes.
Trina Solar has developed exceptionally strict testing procedures. Since wafer quality is a key factor for cell and module performance, Trina Solar wafers are closely examined as part of the quality control process.
Cells
In the next step, the wafer surface is treated in a wet bench. Wafers are placed in various baths for cleaning, etching and rinsing.
After completing the surface treatment, the wafers are dried by hot air.
In a further processing step, a negatively charged coating is applied to the positively charged wafers in a diffusion furnace at temperatures ranging from 800 to 900 degrees using phosphorus gas.
The phosphorus atoms diffuse into the wafers’ surface. And, as a result of such doping, the surface changes from positive to negative.
After edge insulation, in order to reduce cell reflectivity, the cell is coated with a layer of silicon nitride, giving the cell its blue color.
The hydrogen contained in the silicon nitride also significantly enhances cell performance.
Contacts, made of silver paste, are screen printed onto the front of the cells to add to act as a conductor for the electricity generated by the cell.
The contacts are subsequently burnt under the cell in a firing furnace. The high temperatures cause the silver to become embedded in the surface of the silicon layer, forming a reliable electrical contact.
The completed cells are sorted according to efficiency levels and optical criteria. Each cell is assigned to a performance and quality class.
Modules
To assemble solar modules, we interconnect multiple cells by taping and stringing the cells into the desired electrical configuration.
The lines of cells are laid out and assembled between glass, EVA (Ethylene-vinyl acetate) and a back sheet.
The module is then laminated in a vacuum and cured by heating.
An aluminum frame and a junction box are then attached to the laminated module.
As part of our quality process, all finished modules go through a series of tests before they are packaged.
Using an infrared camera, the first test screens for micro cracks at the cell level. The module is then flash tested as a final test of quality.
Modules are then packed in environmentally friendly packaging. Our unique packaging also protects the product in transit by reducing the inherent stress on the modules.
At Trina Solar we run a series of tests on randomly selected modules. The first is a mechanical loading test in which we determine the resistance of the module under harsh wind, snow and static loads such as ice.
Our modules are also tested for resilience in the event of heavy impacts. The test simulates an installed panel on a tiled roof or facade. Each part of the panel can be tested.
At Trina Solar he have also developed proprietary tests such as the Highly Accelerated Stress Test also known as the HASTEST.
This test helps us understand how materials and components change over time. In turn, this allows us to confidently offer our customers a 25 year power warranty on our modules.
We also use an infrared test to analyze the temperature of the module when operating under the sun.
Our modules go through 8 different testing chambers to assess the behaviour of the panel under heavy humidity, UV exposure and harsh weather conditions like heat or hail.
Trina Solar’s growing global presence includes offices in Barcelona, Munich, Seoul, Shanghai and San Francisco as well as a team of local sales managers in each key European country to provide our customers with immediate, reliable service.
Independent tests have recognized Trina Solar panels as one of the world’s top performers.
In 2008, TUV energy yield ranked Trina Solar Panels second best performer among 14 leading international manufacturers.
In a recent on site test, supported by the Australian government in the desert Trina Solar panel also ranked second best crystalline silicon module in terms of power generation.
Such are the tangible results of our state of the art internal testing laboratory. Combine this with one of the most competitive cost structures in the industry and you get the best solar value.
Only by matching an efficient cost structure with proven performance will we, as an industry, achieve grid parity. And at Trina Solar we have both.
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