Framing the Debate

Tapes vs. silicone in solar module manufacturing

Framing of solar modules presents a major pain point for manufacturers tasked with securing the frame to the PV laminate with greater speed and efficiency. InterPV sat down with Geoffrey King, Marketing Manager, Renewable Energy, Saint-Gobain Solar, to discuss the pros and cons of available market solutions, including frame tapes and silicone sealants as well as next-generation technologies that promise to revolutionize the process itself.

Edited by Jeanny H. Lim (swied@infothe.com)

What are the challenges that manufacturers face during the framing process?

Solar module manufacturers confront several challenges in the framing process, but the pressure to increase production efficiency and capacity on the line remains one of their most significant hurdles. One way to address this issue is to select the right materials that can allow for fast framing while also ensuring high-quality modules.

Popular choices for adhering frames to modules include bonding tapes and silicone sealants, each bringing its own benefits. Tapes provide fast adhesion with immediate handling, while silicone sealants require time to cure before handling; if the framed module is moved too soon, the integrity of the unit could be jeopardized. Also, the application of silicone sealants often results in excessive overflowing between the frame and the edge of the module, requiring extra cleaning and subsequent increased labor time on the line. A simple tape solution, which combines the flexibility and durability of an elastomeric foam substrate and the strength of acrylic adhesives, can be implemented to eliminate the production delays associated with curing.

What is the impact of adhesion choice on module performance?

Both silicone and tape options are designed to last more than 20 years, matching the average 20- to 25-year lifespan of modules, but production missteps can compromise durability, efficiency and longevity. For instance, if residue from the silicone adhesive is not properly cleaned, it can interfere with the module’s ability to capture sunlight, thus reducing the cell efficiency. Additionally, if a module’s frame is disrupted before the silicone solution has fully cured; the poor joint could adversely affect the module’s integrity.

The best way for manufacturers to prevent these production missteps is to select the adhesion option that works best in the context of their operations. A streamlined framing process that matches the speed of the line will ensure high-quality modules.

What factors should manufacturers consider when selecting framing technologies?

Before selecting the right solution for solar module framing, manufacturers must consider the level of automation on their production line. For lines that rely heavily on manual labor, tapes provide the best immediate framing solution due to their ability to provide a fast, clean application with instant adhesion, which enables workers to move the modules quickly through the framing process.

Meanwhile, lines that are highly automated better accommodate pumpable liquid solutions. While silicone was the traditional choice, manufacturers must now address the potential bottlenecks that can arise with this type of framing adhesive. First, silicone sealants require time to cure and cannot be handled immediately after the sealant is applied. Instead of moving straight down the line, the modules will have to be staged to initially cure before they can be handled. This type of process accumulates inventory expenses associated with housing and maintaining the extra modules.

Second, the potential for silicone sealants to overflow onto the module’s surface during the application process poses another challenge. The added step of cleaning excess silicone from the module can slow down the line and incurs extra cost in cleaning supply acquisition and disposal.

Manufacturers have to be aware of how these interruptions will impact the flow of their operations and their bottom line. They will have to tackle these challenges if they hope to speed production, mitigate waste and reduce costs in order to remain competitive.

What new technologies are on the horizon to help manufacturers tackle these challenges?

At Saint-Gobain Solar, we recently launched SolarBond™ InFrame, an advanced framing solution that combines the benefits of both tapes and silicone sealants. It is applied warm in a continuous motion, ensuring both accuracy and high bonding strength immediately after contact with the glass, backsheet and frame. This instant adhesion means the product can be handled promptly after application, eliminating time delays required for curing.

SolarBond™ InFrame is well suited for highly automated application processes since it provides immediate handling capabilities for shortened production cycles. This also eliminates the risk of costly product waste, which can result from the handling of modules framed with silicone sealants when they are not fully cured. As a result, manufacturers can reduce the costs associated with damaged products, slower production cycles and inventory storage during the time that the silicone sealant takes to cure. 

As with silicone sealants, SolarBond™ InFrame offers the opportunity for precision application. However, it also helps manufacturers avoid the mess and resulting cost of cleaning labor incurred by the runoff of liquid sealants. The foamed material fills the aluminum channel in the frame, even in the corners. This eliminates the risk of water collecting in the frame. What results is a strong, long-term, weather-resistant bond for a durable final product.

When used with Saint-Gobain Solar’s patented single-piece frame, SolarBond™ InFrame also reduces the number of corner keys or other mechanical fasteners such as screws required to secure the corners of the frame around the module, using just one instead of four fasteners typically required for both tapes and silicones. This can take steps out of the production process and reduce component expenses, further decreasing module costs.

Solar module manufacturers are in the business of alternate energy solutions, so it follows that they would want to enhance the sustainability of their own operations. Which framing solution offers the most in sustainability benefits?

Each technology has its advantages and disadvantages. As I mentioned before, silicone sealants are pumpable for application on an automated line, but can overflow from the frame, creating material waste and requiring an additional cleaning step. For this, manufacturers will need to use additional cleaning solutions, often solvent based, further compromising the sustainability of their operations. The disposal of cleaning supplies can also be costly to the module maker and the environment. Cleaning rags are often covered with residual silicone which may be classified as a hazardous waste.

Tapes are considered more sustainable as they are pre-sized for the specific module design to prevent material waste during the production process. However, both tapes and silicone sealants require four corner fasteners; the reduction of material is a key sustainability goal at most OEMs across industries.

There is one framing technology that does stand out from the other options in enabling sustainability advantages. By providing instant adhesion, immediate handling capabilities and a precision application, SolarBond™ InFrame combines the best of both worlds in minimizing wasted energy and materials on the line. By ensuring a high-quality module that can withstand the challenging environments, it also prevents product waste─another step towards increasingly green manufacturing in the solar industry.

Jeanny H. Lim is Editor-in-Chief of InterPV. Send your comments to swied@infothe.com.

For more information, please send your e-mails to pved@infothe.com.

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