Visitors to this year’s EU PVSEC can look forward to new trends and developments in the photovoltaic industry. As the leading global manufacturer of adhesives and sealants, Henkel will also be there (L3/H1/A14), presenting an extensive product portfolio for automated production of solar modules.
Ingot bonding and wafer cleaning
The photovoltaic industry will soon be taking a development leap in wafer production. Conventionally, wafers are rapidly and precisely sliced out of silicon ingots with a wire saw. The entire ingot is bonded to a glass plate and the workpiece holder to ensure reliable processing. After the slicing process, the edges of the wafers are still fixed to the glass plate via the adhesive and the two parts then have to be disbonded through the application of acetic acid at high temperatures.
Under its Loctite brand, Henkel has developed a new two-component epoxy adhesive which cures ultra-fast, resulting in high-strength and extremely reliable bonding even of extremely thin wafer edges. The new technology also offers the unique advantage that the adhesive can be removed easily and without residues during the following cleaning process, simply with water at a temperature of approx. 60°C. Acetic acid, which causes problems due to its corrosivity, is thus no longer necessary to disbond the wafer from the glass plate. Since there is no more risk of acid attack, the cleaning equipment can be manufactured from less costly materials with a lower level of corrosion resistance. Another plus for manufacturers and line operators is the elimination of odor nuisance at the workplace.
As a systems supplier, Henkel also offers a broad range of industrial cleaning products ensuring impeccable results during wafer cleaning. At the pre-cleaning stage, P3 products help to remove residues from the slicing process. The lubricant properties of these products also make it easier to separate the individual wafers from one another – a distinct advantage that improves the overall process. During the main cleaning process, Henkel cleaners remove all silicon scraps, acid and adhesive residues. The result: perfectly clean surfaces.
High-strength frame bonding within seconds
Another true innovation is Henkel’s new hotmelt adhesive Terostat MS 500 for framing crystalline solar modules. The patented adhesive technology based on modified silane polymers excels thanks to its very high initial bond strength directly after assembly. This makes it outstandingly well suited for fully automated framing of crystalline modules. Unlike conventional sealing systems, Terostat MS 500 achieves instant handling strength, thereby eliminating the usual waiting time. This accelerates throughput rates, resulting in substantial cost savings. With its ease of handling, Terostat MS 500 also presents convincing advantages over conventional fixing by means of adhesive tapes, as there is no need to perform additional steps such as changing reels or disposing of release paper. In addition to outstanding primerless adhesion to glass, metal and plastics, Terostat MS 500 notches up even more points thanks to its excellent resistance to weathering, providing high-performance all-around sealing that ensures long solar module life.
Flat lamination for flexible modules
Henkel is also setting new standards in flexible module production with the introduction of Terostat MS 642. Thanks to a newly developed slot nozzle system, it is now possible to perform fully automatic flat lamination at high speed with a two-component Terostat MS product. This product crosslinks chemically, thus producing a durable yet elastic bond line with high weathering and temperature resistance.