Embedding photovoltaic modules more quickly

Apr 03, 2013
Scientists are laminating a solar cell at CSP in Halle. The process is twice as fast as it used to be. Credit:  Fraunhofer CSP

The market for solar modules is highly competitive. For this reason, companies must save on costs, such as by using a new process. It embeds the cells twice as fast into their protective plastic sheathing – and therefore saves time and money.

must endure a lot: snow, hot summer days, rain and humidity. To provide maximum protection to the cells, the manufacturers embed them in plastic, usually in ethylene vinyl acetate (EVA). The principle is that they laminate the cells in the first step. For this, they encase the cells in a and heat it up. Once the plastic is soft, the entire stack is pressed together in the laminator so that it flows well around the cells and encases them. This process vulcanizes the plastic – in other words, it crosslinks it (meaning that a type of rubber is created). The advantage is that the material can no longer be melted once it is in this state; it is more stable and protects the cells better against mechanical and . For the crosslinking, the solar cell plastic stack is heated in the vacuum laminator to a temperature of up to 150 degrees Celsius; this high temperature provides the "starting signal" for the crosslinking. The for the vulcanizing are rather long, however the stack of cells must remain in the laminator for about 20 minutes, sometimes even longer, driving production costs up.

Less than eight minutes for laminating

The manufacturers can counteract this cost pressure on either the process or the materials side, meaning you are able to optimize the process yourself or use better materials. Scientists from the Fraunhofer Center for Silicone Photovoltaics CSP in Halle will, from now on, support manufacturers on the process side jointly with colleagues from LANXESS: "We have modified the lamination process so that it only takes about 7 to 8 minutes instead of 20 minutes. We were therefore able to reduce the duration of the total process by more than 50 percent," says Dr. Stefan Schulze, Polymer Materials Team Leader at CSP. "In comparison to the standard process we are therefore able to laminate twice as many modules on one system, which directly positively affects the production costs per module."

The researchers were inspired by printing ink for news prints, which vulcanize in a few seconds after being exposed to a UV light. The crosslinker used by LANXESS worked in the same manner – activated by UV radiation instead of by high temperatures, it crosslinks the plastic within a few seconds while maintaining the same quality. The reason for that were the plastic films. If the usual additives are used in the plastic, then care must be taken when mixing the ingredients to always stay below the crosslinking temperature – meaning that the mixing has to be carried out very gently. For this reason, the resulting film is often not very homogenous. "However, if we crosslink the additives using UV radiation we are able to mix aggressively. We therefore achieve homogenous films and thus an improved crosslinking of the plastic," Schulze makes clear.

The researchers at CSP developed the UV crosslinking process within the Fraunhofer Innovation Cluster SolarPlastics. They are looking for answers to the following questions: How can the process be controlled? What temperatures are required? And how much radiation is required? The LANXESS employees took care of the material, meaning the composition and the type and amount of the UV crosslinker. The CSP already has a pilot plant for crosslinking where the scientists are optimizing the four parameters – the amount of radiation, the temperature, the height of the lamp and the feed rate at which the modules traverse under the UV lamps. "The process is operational," says Schulze. Interested manufacturers need not fear high costs for retrofitting their production facilities; only one UV lamp would have to be added.

Explore further: Old timey car to replace NYC horse carriages shown

add to favorites email to friend print save as pdf

Related Stories

Plastic solar cells pave way for clean energy industry

Sep 20, 2012

(Phys.org)—A Flinders University researcher has been developing a cheaper and faster way of making large-scale plastic solar cells using a lamination technique, paving the way for a lucrative new clean ...

Flexible films for photovoltaics

May 26, 2011

Displays that can be rolled up and flexible solar cells -- both are potential future markets. Barrier layers that protect thin-film solar cells from oxygen and water vapor and thus increase their useful life ...

Anti-aging elixir for solar cells

Jul 03, 2012

Photovoltaic modules deliver power without risks to the environment and climate. But solar-power is expensive. Therefore, it is imperative that the modules last as long as possible, 25 years or more. Fraunhofer ...

Recommended for you

Obama launches measures to support solar energy in US

19 hours ago

The White House Thursday announced a series of measures aimed at increasing solar energy production in the United States, particularly by encouraging the installation of solar panels in public spaces.

Tailored approach key to cookstove uptake

19 hours ago

Worldwide, programs aiming to give safe, efficient cooking stoves to people in developing countries haven't had complete success—and local research has looked into why.

Wireless power transfer achieved at five-meter distance

20 hours ago

The way electronic devices receive their power has changed tremendously over the past few decades, from wired to non-wired. Users today enjoy all kinds of wireless electronic gadgets including cell phones, ...

User comments : 0

More news stories

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...

Venture investments jump to $9.5B in 1Q

Funding for U.S. startup companies soared 57 percent in the first quarter to a level not seen since 2001, as venture capitalists piled more money into an increasing number of deals, according to a report due out Friday.

White House updating online privacy policy

A new Obama administration privacy policy out Friday explains how the government will gather the user data of online visitors to WhiteHouse.gov, mobile apps and social media sites. It also clarifies that ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.