New plastic film protects solar panels against glass

For many years, solar companies have been trying to produce lightweight, flexible solar panels that can be transported cheaply and are easy to install (they have a large area for deployment). But they have been blocked because of the lack of good and affordable glass alternatives.

Now, 3M believes they have found a solution. This week, the company introduced a plastic film, which it claims rivals glass because it protects active materials from moisture damage in solar panels and saves money for manufacturers and their customers.

This protective film is a multi-layer, fluoropolymer film that can replace glass and serve as a protective cover to protect solar panels, said Derek DeScioli, who is 3M renewable Energy Department Business Development Manager. Manufacturers cover solar panels and tightly seal them to protect them from moisture and other weather conditions, all of which can fatally damage solar cells.

This kind of film makes 3M company meet the demand, it is the demand of the solar panel manufacturer, especially the manufacturer that produces certain thin film solar battery, their demand is the glass substitute product. Glass has always been a protective material, it was chosen because it is cheap, and it can withstand the effects of the weather, durable enough to last for decades. The vast majority of solar panels today are made of glass for the top cover. However, glass also increases the weight and volume of the solar panel, and it must be carefully packed so as not to break, which increases transportation costs. After replacing the glass, this new type of film does not require a support frame. The support frame is particularly useful because some roofs cannot tolerate much weight. Blending solar panels into the roof can also overcome the aesthetic objection of the homeowner.

"Flexible solar panels all have these perfect benefits, but then, you will encounter a problem, that is, how to package them. For many years, people did not pay attention to this problem," Steven Hegedus (StevenHegedus He said that he is a scientist at the Energy Conversion Institute at the University of Delaware.

Protecting solar cells with plastic is not a new idea. You can see plastic solar cells in camping gear and novelty devices. For example, some backpacks have a built-in solar charger. But this type of plastic film is not designed to withstand long-term outdoor exposure, such as 20 to 25 years of exposure, how long this is, and solar panels should be able to continue to use such a long time, Heiguus said.

Several other companies have recently begun to promote plastic closures for flexible solar panels. 3M's materials have orders of magnitude higher performance and can remain water-resistant, which is the key to longevity.

United SolarOvonic is the only large-scale film manufacturer and has launched flexible solar panels for many years. The Michigan company uses amorphous silicon, which is also not sensitive to moisture, like other emerging compounds. The company's amorphous silicon solar panels can only convert about 7% of the sunlight, which of course refers to sunlight shining on the panel, to electrical energy. Due to the low conversion rate, Uni-Solar's products are less desirable. . The fluoropolymer resin used by Uni-Solar is from DuPont and is used as a surface coating for panels.

The preparation of solar cells requires semiconductor materials, including copper, indium, *, selenium (CIGS), which may be twice as efficient as amorphous silicon, but they are more sensitive to humidity and therefore need to be better protected from moisture attack. Many CIGS manufacturers have found a manufacturing process to store this compound on rolls of flexible metal foil or plastic.

The companies said that they can produce such solar panels faster, using this roll-to-roll process; the importance of achieving higher output is that they can reduce production costs. But they have always relied on glass for the front plate because of the lack of suitable plastics. In addition to CIGS solar panel makers, 3M's targeted developers have also developed cadmium telluride and organic thin films, Desioli said.

The 3M company in Minnesota is developing a more durable front ferrule. The result of the study is a plastic film that is 23 microns thick and is much thinner than 3,000 microns thick. This glass is commonly used in today's solar energy. Panel, Desioli said. The company uses fluoropolymers because it is not easily penetrated by water and is resistant to high temperatures and UV rays. 3M also designed a film to prevent it from reflecting too much sunlight. 3M company said that its film can achieve the effect of water vapor penetration rate of less than 0.0005 grams of water per square meter per day. Other front protective films will seep through hundreds of times more moisture.

Desioli said that the film can also be rolled with the same roll-to-roll process that can be used to store thin-film semiconductors, which can reduce production costs. Flexible solar panels can also be larger than glass panels because the versatility does not require a bracket system and is easier to transport. The time and cost of assembling a large panel assembly can be much lower than assembling many small panels, he said.

"The main value is that our film allows manufacturers to produce larger components and use the roll-to-roll process," said Desioli. He said that although the cost of the material itself is not lower than glass, it will reduce the overall cost, because it can save manufacturing and installation costs.

3M now manufactures the film on an exemplary production line and plans to mass-produce it next year. The company said that their customers have already been in a team, but Desioli refused to disclose the customer's name.