Just a few weeks after DuPont announced a new product for its ionomer-based encapsulant line, we caught wind that Cytec is developing its encapsulant targeted at the thin-film market. The company plans to leverage its experience in UV-cured materials used in laminated glass applications, and ultimately offer a solution that can be cured in a matter of seconds. Incumbent materials like ethelene vinyl acetate (EVA) and polyvinyl butyral (PVB) take at least ten minutes to laminate.
In addition to faster cure times, both companies claim a key advantage of their products will be a lower moisture vapor transmission (MVT) rate, which helps protect the sensitive semiconductor layers. Having a low MVT rate is especially important for thin-film modules that replace glass with polymer backsheets and frontsheets, since it helps cope with the lower moisture barrier properties of those materials. However, successful solutions must be able to show a clear advantage over PVB for thin-film applications, primarily in raw materials cost. Since most module manufacturers already have autoclave furnaces, it is unclear how much they value improvements in cycle time.
A growing threat for such encapsulant technologies, however, is a practice by module manufacturers to sandwich products in glass and apply a powerful edge sealant, which provides the desired moisture-barrier. Abound Solar is already using such a “filler-free” encapsulation method; and Sharp, one of the world’s largest thin-film silicon module manufacturers, recently announced that it too will pursue frameless glass-glass modules protected by an edge sealant. First Solar, also using a glass-glass construction, uses EVA material for mechanical stability and an edge sealant to slow water and oxygen penetration.
Clients should watch closely over the coming years to see whether or not module manufacturers increasingly value the adhesion and strength of encapsulants over their moisture barrier properties. In our upcoming Solar Components State of the Market Report, we will tackle this topic among other challenges being faced by materials suppliers.