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A PV portfolio defined by innovationA world leader in a number of different market sectors, Henkel is known for its commitment to R&D and its brave approach to diversification. Here, Kornelia Theissen, Focus Segment Manager Solar Western Europe, discusses how the company’s portfolio delivers solutions across the entire value chain for the solar industry.

PES: Welcome to PES, can you begin by telling us a little about the company and how it serves the solar/PV sector?

Kornelia Theissen: Founded in 1876, Henkel operates worldwide in the three business areas: Laundry & Home Care; Cosmetics/Toiletries; and Adhesive Technologies. Henkel employs about 48,000 people and reported sales of 15,092 million Euros in fiscal 2010. With its Adhesives Technologies, Henkel is a worldwide leader in bonding, sealing and surface treatments. As such we are able to fully embrace new trends, foresee new needs and provide appropriate innovative solutions and sustainable products. Manufacturers know and rely on trusted brands such as Loctite, Purmelt, Teroson and Terostat.

Solar power will be a key source of energy in the future. As a systems provider, Henkel is playing a major role in the breakthrough of this innovative technology – with high-tech adhesives, sealants and cleaners. With our product range, we cover the entire photovoltaic value chain. Henkel’s specialists continuously strive to improve existing solutions in line with market needs.

No matter what kind of application is involved – electrically or thermally conductive bonds, structural joints and seals with extreme resistance to weathering, or cleaning tasks of all kinds – Henkel’s portfolio of innovative adhesives, sealants and cleaners delivers solutions across the value chain for the solar industry, serving both photovoltaic and solar thermal needs.

From wafer production, which requires both adhesives to fix the silicon ingots

and high-performance cleaners, to the manufacture of thin-film and crystalline solar modules, as well as their integration into buildings, Henkel experts on solar technologies repeatedly analyse the specific market needs for each particular application and offer tailor-made solutions that go far beyond the delivery of products alone. If desired, Henkel will also provide focused assistance in planning new concepts and obtaining the necessary approvals – directly from the relevant institutions.

Moreover, our service teams are ready to help at any time with technical support regarding the different applications, including consultation with machine suppliers. With its innovative solutions and concepts, Henkel also helps its customers to strengthen their own innovative process.

PES: How much of your total business is dedicated to the solar/PV market? Is this an area in which you foresee future growth?

KT: Yes, we clearly see that solar power will be a key source of energy in the future. The photovoltaic industry is therefore a strategic focus market for Henkel. Proof of this is the fact that we use a considerable amount of resources on research and development in this field. Behind all this is a dedicated team of different specialists in engineering, product development, market research and sales. Our labs and equipment and our people enable us to play a major role in the breakthrough of solar technology – with high-tech adhesives, sealants and cleaners.

PES: The photovoltaic industry is striving to increase productivity while lowering

manufacturing costs. How do your solutions facilitate this?

KT: Developing efficient products for the photovoltaic industry requires a 360-degree approach. Henkel’s high-quality, tailor-made adhesives, sealants and cleaners provide highest quality and may improve yield rates during the expected lifetime of a PV module. All our concepts are designed to enable highly automated production processes, increase production speed and avoid excessive packaging waste. Higher utilisation can be realised and quality complaints generally become a rare occurrence. In comparison to traditional concepts, capital expenditure can be reduced, for instance by saving on buffer systems that become redundant with most of our products. Overall, the manufacturing cost per module, or per manufactured Watt-peak, can be reduced significantly when using our products.

PES: Can you tell us a little about the UV, temperature and weathering resistance of your adhesive products – as you’ll appreciate, these are crucial factors.

KT: It is our aspiration to improve existing solutions in line with the market needs. Therefore, our products are specifically designed to meet the stringent requirements of the solar market: they show superb long-term resistance to severe weathering conditions as well as UV radiation. To give an example, the excellent elastic behaviour of our Terostat MS range makes these products ideal for compensating the difference in thermal expansion of the bonded parts – such as glass and metal – while also showing

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excellent snow and wind load capabilities. Our products react chemically with the bonded parts, and cross-linking leads to this extreme performance in addition to excellent primerless adhesion to glass, metal and plastics.

PES: Similarly, what kind of a lifetime can a module manufacturer expect from your sealants?

KT: To ensure highest reliability of our products, we run aging test programs of over 3,000 hours. Henkel’s adhesives for the solar market have been damp heat tested up to 85°C and 85 per cent relative humidity. In addition, they withstand humidity freeze tests ranging from minus 40°C to plus 85°C as well as thermal cycling test from minus 40°C to plus 85°C. These results show a performance more than three times better than the requested testing time for the IEC 61215/61646 certification.

In general, we can look back on over 20 years of professional experience with our Terostat MS sealants range. During all this time, we not only met but exceeded the industry standards. This gives us the confidence to assure a 25-year lifetime for these adhesives, when applied professionally.

PES: Do the environmental conditions – temperature, moisture, etc. – within a module factory impact upon the success of the curing of your products?

KT: Most of our products for the solar industry are two-component materials. As such, they are completely unaffected by humidity. However, ambient temperature can indeed influence the cure speed significantly; an effect that can be used in a positive way, when handled appropriately.

But generally, factories are air-conditioned, therefore no major fluctuations in environmental conditions are expected during the manufacturing process. Our products are designed to provide cure rates that ensure handling strength right after the manufacturing process, allowing further manipulation and transport without the usual waiting time. Final curing of the two-component system can then take place during transport or storage.

In order to make sure that product cure rates, environmental conditions and process speed are well aligned, Henkel experts carefully discuss with our customers the expected conditions in the production process.

PES: Where is your main focus of your applications?

KT: Apart from solutions for wafer manufacturing, such as adhesives for ingot bonding and wafer cleaners, the main focus of our applications lies on adhesive and sealant solutions for the backend of PV module manufacturing. Here, highest reliability and fast process speed are the predominant requirements.

For the assembly of thin-film solar substrates Henkel designed Hysol Eccobond CE3103WLV, an electrically conductive adhesive. It overcomes challenges with unstable contact resistance posed by older-generation ECAs (Electrically Conductive Adhesives). Based on research which concluded that electrochemical corrosion on copper and tin in elevated temperature and humidity conditions was the primary culprit of contact resistance instability, Henkel developed an ECA to overcome this challenge.

By introducing advanced corrosion inhibition characteristics into Hysol Eccobond CE3103WLV, the material enables stable electrical contact resistance between transparent conductive oxides and tin terminations through 1,000 hours of plus 85°C at 85% relative humidity. This advance allows manufacturers to now employ a low temperature process, thus reducing energy consumption and device stress.

Also part of Henkel’s portfolio of solar ECA solutions is Hysol Eccobond CA3556HF. As an alternative to traditional solder connections used for c-Si solar modules, which can be problematic for emerging thin, fragile solar cells, Hysol Eccobond CA3556HF has been formulated to deliver low temperature curing at 150 degrees centigrade and an exceptionally fast cure time of five seconds.

The award-winning material provides an excellent bond between the Ag and SnPbAg

Henkel provides solutions for module framing, junction box bonding and electrically conductive bonding applications shown on a crystaline module

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coated tabs and the c-Si cells, delivering a stable and reliable electrical connection over the life of the module. But, it’s not just c-Si processes that benefit from Hysol Eccobond CA3556HF; thin-film module manufacturers have also successfully incorporated this material into processes that dictate low-stress, fast curing interconnection of cells and ribbons.

To bond PV junction boxes fast and efficiently, the new Loctite 5610 was developed. It facilitates highly automated processes that don’t require expensive buffer systems or tapes for initial fixing of the box. Loctite 5610 is a superb primerless adhesive for plastic backsheet materials and glass. The pasty consistency allows for gap-filling and balancing tolerances. Applied on the perimeter of the junction box, it has a quick initial bonding strength (after three to five minutes). Its excellent long-term resistance to harsh weathering conditions was proven in long term aging tests. All in all, Loctite 5610 is a very reliable solution for a key element of the PV module.

Module framing is another focus application of Henkel during the PVSEC in Hamburg in September. We will show that Terostat MS 650 is the state-of-the-art solution for high performance bonding and sealing of module frames. It shows fast strength build-up within five minutes. Its high speed as well as higher uptimes (eliminating tape spool change) will lead to a significant reduction of process cost per module. Product quality will benefit as well, because Terostat MS 650 covers the entire module edge, which makes the corners and edges watertight. Finally, the product is supplied in bulk in drums or pails, so that packaging waste is negligible.

Module production cost represents only 50 per cent of total PV cost. The remaining 50 per cent relates to installation. We address this chunk of cost with our solutions to bond back rails to glass and plastic backsheets. They enable easy installation procedures. Henkel has a broad product range for this application addressing different requirements of different customers. Terostat MS 647 is our recently developed high performance elastic bonding product for this application.

It shows excellent flexibility even at low temperatures, which results in an outstanding resistance to high mechanical and wind loads in all seasons. It is fast curing, fills gaps and balances tolerances in the substrates due to its pasty consistency. Its fast curing performance contributes to high speed production processes without compromising on bonding properties.

It goes without saying that all our products must pass the test programs mentioned earlier to meet the high standards of the photovoltaic industry.

PES: How important is sustainability to the company?

KT: Sustainability is a core element of our corporate culture and therefore very important to Henkel. For more than 130 years now, Henkel has been working toward achieving sustainable development. This means that through brands and technologies, as a company and as an employer, Henkel has been striving to meet the needs of people today without compromising the development opportunities of future generations. This ambition applies to all of the company’s activities – throughout the entire value chain.

For Henkel, sustainability is not an end in itself, but generates value for the company and for customers. It gives a competitive advantage when it creates economic, ecological or social benefits for the customers as well. Henkel offers customers first-class performance while simultaneously helping them to operate sustainably throughout their value chain. For example by developing products that make production processes considerably more efficient than conventional solutions.

Henkel’s commitment to renewable energy sources is also illustrated by our latest Sustainability Report. Among other achievements in the field of sustainability, the report describes how our expertise in adhesive technologies and the commitment of our team contribute to the success of Novatec Solar in building solar thermal power plants.

PES: What characterises the relationship between Henkel and its customers?

KT: Henkel’s professional service begins with support in the selection of a suitable product solution for the customer’s requirements, as well as the application equipment for the recommended product. It is also one of our competencies to design the production line together with

Henkel’s solutions improve design and installation of solar modules: Backrail bonding shown on thinfilm glas/glas module

the equipment manufacturer, keeping the principles of sustainability and environmental protection in mind.

In addition, Henkel experts support our customers in optimising their processes. We focus on improving product quality and reducing production costs, for example by implementing highly automated production processes and facilitating significantly increased production speed. Because we analyse the specific market needs for the solar industry, we are able to develop solutions for new materials, including the appropriate application and performance tests.

During production start-up, Henkel provides technical support through on-site assistance by Henkel experts. Experienced specialists help to adapt the production processes to a new Henkel technology. Customised technical training for customers’ staff in one of Henkel’s worldwide technology centres or on site at the production line is another of our services, along with the optimisation and fine-tuning of process parameters for the Henkel product. Risks, when introducing new applications or substrates, are minimised by running prior tests with materials in Henkel’s in-house laboratories. Our certified Analytics department is able to detect causes of failure or other phenomena with latest state-of-the-art analytical equipment.

Finally, Henkel provides quality checks according to official regulations, as well as individually designed tests according to the customer’s needs. The evaluation of potential process improvements is just as much a part of our service portfolio as maintenance, repair and overhaul. For maintenance and repair, Henkel offers a wide range of adhesives, sealants, lubricants and cleaners.

For more information, please visit: www.henkel.com

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Solutions for the Photovoltaic IndustryElectronic Materials, Adhesives, Sealants and Cleaners

Our Competencies

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�� Environmentally�compatible�solutions

�� Comprehensive�system�of�products�and�services

�� Cooperation�with�machine�manufacturers

�� Global�team,�global�presence�–�local�support

Your Benefits at a Glance

�� Improve�your�process�and�product�quality�through�–�fast,�highly�automated�processes�–�more�durable�products

�� Reduce�your�overall�costs

�� Profit�from�various�approvals

�� Benefit�from�ongoing�product�development

�� Gain�a�long-term�partner

One Source for all your Needs

Developing�efficient�solutions�for�the�photovoltaic�industry�requires�a�360-degree�approach.�Henkel’s�high�quality�tailor-made�adhesives,�sealants�and�cleaners�improve�quality,�enable�highly�automated�production�processes,�increase�production�speed,�and�thus�decrease�your�manufacturing�costs.�The�innovative�Henkel�solutions�have�an�excellent�reputation�worldwide.

Henkel AG & Co. KGaA | Phone: +49-211-797-3376 | info.solar@henkel.com | www.henkel.com/solar

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