Image via: osamu_ito on Flickr.com3M Solar
Ever wonder how your solar panels are held together, just silently doing their job day in and day out, taking a beating from all of the seasons, while up on your roof? Sundar Damodaran, Global Business Manager for Tapes & Adhesives under the Renewable Energy Division, lets us in on the sticky little secret. 3M has been in business for over 100 years, but has only recently consolidated their product line to look specifically at solar solutions. They think their product can offer not just an alternative to glues and screw, but also save companies time and money during production while offering long-term performance. Solar panels are warranted for 20+ years, but are estimated to last 40 or more years. Whatever holds all of those parts together has to be something built to last. 3M thinks tape is that answer. The problem with using glue is that you have to wait for it to cure. The problem with screws or other fasteners is that you're cutting more holes into the product. Tapes on the other hand can be applied and sent down the production line instantaneously. For a company manufacturing a solar panel a minute, it costs time and money to wait for glues to cure.
Most of what goes into the adhesive are petroleum-based products so while the price might go up, the resources will be around for awhile. At the same time, 3M is looking at trying to phase out some of their "nastier" ingredients, like solvents. They are working on making solvent-less products to reduce their pollution from their smokestacks.
Where Can You Find Tape on Solar Panels?
Actually there are quite a few places where tape is holding parts together. Tapes hold the glass panels onto the metal frames. Seems sort of dicey, but since 3M already has tapes holding glass windows onto tall skyscrapers, they know their technology will work. The tapes also adhere the junction box onto the back of the solar panel. Third the tapes adhere all of the signage to the panel, which will be very important 20 years down the road when someone comes out to service your panels and needs to know the voltage, watts and amps for this panel.
That's not all that those tapes can do. Some uses are just cosmetic, such as using the tape to hide different wiring or other things that aesthetically don't want to be shown. In addition, 3M makes Charge Collection tapes, so instead of installing a diode, you just put a tape on the top and bottom, or the left and right, and it collects all of the charge along the entire length of the tape. Then 3M also has a Bus tape, which brings the current collected from the "charge collection" tapes up to the junction box without collecting anything else along its route. Seems pretty advanced for something as "simple" as tape.
Since solar panels last for such a long time and are rated to withstand hurricane-force winds (seriously, if the panels come off your roof, your roof is probably coming off with them), the glues also have to be able to withstand extreme temperature and wind variations. According to Damodaran, some of the harshest conditions occur in the lamination process during manufacturing. The panels themselves are exposed to 150 degrees celsius, albeit for a short period of time, but the tapes have to withstand these temperatures, which is much higher than they will ever experience out in the field.
Currently 3M is working on figuring out how to meet solar panel manufacturers' needs and as the market changes figure out how they can help. Right now flexible panels are getting more press and so 3M is working to offer tapes that work in these applications. Asked whether 3M has an plans to make a similar paint-on solar panel, Damodaran said that "At this time 3M is not in the business of manufacturing solar panels or paint-on solar panels...not yet."
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