BIPV Building Integrated PhotovoltaicsBIPV or custom solar panels often include glass. There are several options to make panels based on the materials used in regular panels.
EVA is used to cushion the cells, so above and below. It is a thermoplastic material that was once proposed because it is dirt cheap. For solar applications however the price is about 14 Euro per m2. It requires a melting process.
Epoxy Epoxy is used to encapsulate cells. It can remain clear and should be a usefull candidate. It is not advertised as such. One reason may be that it is cheaper.
Silicons Silicons can be stable, elastic, optically clear. They are an ideal choice, but the price of the mateiral is about 1 Euro/Watt. If one submerges 1 m2 of panel in silicons this takes about 0.7 to 1 liter. Silicons can be RTV (room temperature vulcanizing) in which case on can simply wait for it to cure. This is a very low energy solution.
Some heat cured silicons need degassing, which requires an expensive vacuum machine. This is mainly because small bubbles become big bubbles when heated.
ETFE This is an interesting material, it is durable, highly transmissive, cheap and very strong. It can serve as the outside layer, saving weight and cost when compared to glass. ETFE melts and can be welded, which makes it interesting to see if it can be used without EVA.
LaminatesMost common for panels
-Backplate (Acrylic, PVC)
Acrylic method patent (1983)
Polyurethane for solar applications
Polyamide encapsulant patent
Poly urethane patent (2006) (contestable)(known in 1988)Another patent
Clearpur (are working on formula)
Cold Bended Glass laminate
Etimex EVA sheets EVA
PVB (its use) product
ETFE (Teflon, Fluon, Hostaflon, Ertaflon en Gaflon)
ECTFE (Halar) LeverancierF-Clean Example of use
Tabbingflux pens Watch out with the fumes!
spot welding Parameters
Cleaning Solder ResidueThe flux pen acid is real nasty stuff, it will burn the throath and lungs. Use gloves in a well ventilated room, preferably with vetilation removing the damps to outside. Ultrasonic cleaner plus water and soap.
Ultrasonic cleaner of the right size
Resin and lamination sourcesCesense
Lamination processes1. Vacuum laminator or bag
2. Vacuum ring
3. Nip Roller
4. Overpressure process (inner tube balloon)
5. Degassing > 29 inch hg
VideosHow they are made
Top layer Transmissivity (Glass and Plastics)
|Polymethyl methacrylate (acrylic) (Acrylate, Lucite, Plexiglass)||0.89|
|Polycarbonate (Lexan, Merlon)||0.84|
|Polyethylene terephthalate (polyester) Mylar)||0.84|
|Polyvinyl fluoride (Tedlar)||0.93|
|Fluorinated ethylene propylene (FEP Teflon)||0.96|
|Fiberglass-reinforced polyester (Kalwall)||0.87|
CellsThe cells commonly available are:
3 by 6 1.8 Watt
5 by 5 2.5 Watt
6 by 6 3.6 Watt
If you can get tabbed cells that is much better (soldering the front is a pain). Read Ebay offers carefully, the actual output of the cells offered can disappoint. 'Short tabbed' or 'Double side tabbed' means recycled. About measuring the cells
Cel manufacturers can be reached here PVCellManufaturers